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1 Answer

Where is the multifunction switch on 2003 ford ranger located for the wiper and dash light


What seam's to be the problem ? Would hate for you to replace the switch an have it not fix the problem .
The wiper's not working ? There is a whole list of thing's that could be the problem . Same for the dash light's ?
Symptom Chart Condition Possible Sources Action
  • The wipers are inoperative
  • Central junction box (CJB) fuse:
    • 16 (30A)
  • Circuitry.
  • GEM.
  • Multifunction switch.
  • Wiper run/park relay.
  • Wiper HI/LO relay.
  • Wiper motor.
  • GO to Pinpoint Test A .
Hooking up a scan tool an checking for DTC'S - diagnostic trouble code's in the GEM module .
GEM Diagnostic Trouble Code (DTC) Index
GEM Diagnostic Trouble Code (DTC) Index DTC Description DTC Caused By Action B1431 Wiper Brake/Run Relay Circuit Failure GEM GO to Pinpoint Test A . B1432 Wiper Brake/Run Relay Circuit Short to Battery GEM GO to Pinpoint Test A . B1434 Wiper Hi/Lo Speed Relay Failure GEM GO to the Symptom Chart. B1436 Wiper Hi/Lo Speed Relay Coil Circuit Short to Battery GEM GO to Pinpoint Test C . B1438 Wiper Mode Select Switch Circuit Failure GEM GO to the Symptom Chart. B1441 Wiper Mode Select Switch Circuit Short to Ground GEM GO to the Symptom Chart. B1446 Wiper Park Sense Circuit Failure GEM GO to Pinpoint Test D . B1450 Wiper Wash/Delay Switch Circuit Failure GEM GO to the Symptom Chart. B1453 Wiper Wash/Delay Switch Circuit Short to Ground GEM GO to the Symptom Chart. B1458 Wiper/Washer Pump Motor Relay Circuit Failure GEM GO to Pinpoint Test E . B1460 Wiper/Washer Pump Motor Relay Circuit Short to Battery GEM GO to Pinpoint Test E . B1466 Wiper Hi/Low Speed Not Switching GEM GO to Pinpoint Test C . B1467 Wiper Hi/Low Speed Circuit Motor Short to Battery GEM GO to the Symptom Chart. B1473 Wiper Low Speed Circuit Motor Failure GEM GO to the Symptom Chart. B1476 Wiper High Speed Circuit Motor Failure GEM GO to the Symptom Chart. B1840 Wiper Front Power Circuit Failure Open/Short to Ground GEM GO to Pinpoint Test A . - All Other DTCs GEM REFER to Section 419-10.
The multifunction switch has nothing to do with the dash light's
Instrument Cluster and Panel Illumination The instrument cluster and panel lighting system is powered through the headlamp switch and the panel dimmer switch. The instrument cluster illumination is controlled by the output of the panel dimmer switch. The instrument panel lighting circuit provides illumination for the:

Oct 23, 2017 | Ford Ranger Cars & Trucks

1 Answer

Limited. What is causing battery drain?


To find out what is draining the battery do a parasitic draw test . How To Perform Parasitic Draw Test EricTheCarGuy Test to be sure , before replacing GEM module .I would also have the GEM checked for DTC'S - diagnostic trouble codes . I would also check the battery saver relay .
SECTION 417-02: Interior Lighting 2000 Explorer/Mountaineer Workshop Manual DESCRIPTION AND OPERATION Procedure revision date: 06/17/1999 Interior Lighting The interior lighting system consists of the following:
  • dome/map lamp
  • rear dome/cargo lamp
  • overhead console/map lamp
  • RH/LH vanity mirror
  • ash receptacle lamp
  • puddle lamps
  • interior lamp switches
  • interior lamp relay
  • dimmer module
  • battery saver relay
  • generic electronic module (GEM)
Generic Electronic Module (GEM)/Central Timer Module (CTM) Controlled Functions
The generic electronic module (GEM) is equipped on four-wheel drive vehicles with power windows. The central timer module (CTM) is equipped only on two-wheel drive vehicles without power windows.
NOTE: GEM/CTM diagnostics are compatible with the scan tool.
The GEM/CTM incorporates the functions of several different modules into one, and offers diagnostics to easily locate and repair concerns affecting the subsystems that it controls.
The GEM/CTM constantly monitors the systems it controls and reports a concern in the form of a diagnostic trouble code (DTC). A DTC can be retrieved with the scan tool through the communication link.
The scan tool is a menu-driven tester that allows the user to run specific tests. The scan tool can isolate faults in the GEM/CTM subsystems through a symptom-driven diagnostic procedure. Connecting the scan tool to the GEM/CTM communication link will not alert the GEM/CTM. If the GEM/CTM is "asleep" when the diagnostic connector is plugged in, the GEM/CTM must be "awakened". If the communication link cannot be established, turn the ignition to RUN.
NOTE: The GEM/CTM has a sleep function to minimize battery consumption. During the sleep mode, the GEM/CTM turns off all outputs and monitors only the following:
  • door ajar (driver door, passenger door, liftgate, LH rear and RH rear doors).
  • key-in-ignition.
  • key in RUN or ACC.
  • two-step unlock switch (unarm switch).
  • digital TR sensor.
  • illuminated entry request (remote anti-theft personality [RAP] module).
If a change of status occurs at one of these inputs while the GEM/CTM is "asleep", the GEM/CTM will "wake up." When the GEM/CTM awakens, it carries out an internal self-test, and begins normal operation. At this point, the GEM/CTM will have all of its functions operational.
The GEM/CTM will go into the sleep mode immediately after both of the following conditions have been met:
  • key in OFF or key not in ignition.
  • after 45 minutes with no change in any wake-up input.
The GEM/CTM control system has two modes of operation; the normal operating mode and the tester-dependent diagnostics mode.
Normal operation of the GEM/CTM can detect errors. An integral part of normal GEM/CTM operation is continuous diagnostic capability. Continuous diagnostics detects errors and changes the GEM/CTM control strategy. There is no warning lamp for the GEM/CTM; therefore, a DTC concern will direct you to the GEM/CTM. Examples of faults that may be detected during normal operation include:
NOTE: The GEM/CTM can only detect open circuit/short to GRD faults when the GEM/CTM is not energizing a load, and short to battery faults when the GEM/CTM is attempting to energize a load.
  • GEM/CTM continuous self-test (RAM, ROM, EEPROM, A/D checking).
  • output driver monitoring (open circuit/short to ground [GRD], short to power).
  • illogical combinations of input signals.

Dec 01, 2015 | 2002 Ford Explorer

1 Answer

4x4 low light on car will not move


The electronic module (located behind the glove compartment) controls the operation of the transfer case in response to inputs from the electric shift motor, 4x4 mode switch, CPP switch, BPP switch, DTR sensor, throttle position output from the PCM, front and rear OSS sensors, and the VSS. Do you know what DTC'S Are ? Diagnostic trouble codes !

P1804 4WD High Indicator Circuit Failure GEM GO to Pinpoint Test C . P1806 4WD High Indicator Short to Battery GEM GO to Pinpoint Test C . P1808 4WD Low Indicator Circuit Failure GEM GO to Pinpoint Test C . P1810 4WD Low Indicator Short Circuit to Battery GEM GO to Pinpoint Test C . P1812 4WD Mode Select Circuit Failure GEM GO to Symptom Chart. P1815 4WD Mode Select Short Circuit to Ground GEM GO to Symptom Chart. P1820 Transfer Case CW Shift Relay Coil Circuit Open or Short to Ground GEM GO to Pinpoint Test B . P1822 Transfer Case CW Shift Relay Coil Short to Battery GEM GO to Pinpoint Test B . P1824 4WD Electric Clutch Relay Circuit Failure GEM GO to Pinpoint Test A . P1826 4WD Electric Clutch Relay Short to Battery GEM GO to Pinpoint Test A . P1828 Transfer Case CCW Shift Relay Circuit Failure GEM GO to Pinpoint Test B . P1830 Transfer Case CCW Shift Relay Coil Short to Battery GEM GO to Pinpoint Test B . P1836 Transfer Case Front Shaft Speed Sensor Circuit Failure GEM GO to Symptom Chart. P1837 Transfer Case Rear Shaft Speed Sensor Circuit Failure GEM GO to Symptom Chart. P1838 Transfer Case Shift Motor Circuit Failure GEM GO to Pinpoint Test B . P1846 Transfer Case CONTACT PLATE "A" Circuit Failure GEM GO to Pinpoint Test B . P1850 Transfer Case CONTACT PLATE "B" Circuit Failure GEM GO to Pinpoint Test B .

P1854 Transfer Case CONTACT PLATE "C" Circuit Failure (GEM Only) GEM GO to Pinpoint Test B . P1858 Transfer Case CONTACT PLATE "D" Circuit Failure (GEM Only) GEM GO to Pinpoint Test B . P1866 Transfer Case Maintenance Required (GEM Only) (4-wheel drive operation can be restored by clearing the DTC and cycling the ignition.) GEM GO to Pinpoint Test B . P1867 Transfer Case Contact Plate General Circuit Failure (GEM Only) GEM GO to Pinpoint Test B . P1874 Automatic Hall Effect Sensor Power Circuit Failure GEM GO to Symptom Chart. P1875 Automatic Hall Effect Sensor Power Circuit Short to Battery (GEM Only) GEM GO to Symptom Chart. P1891 Transfer Case Contact Plate Ground Return Open Circuit GEM GO to Pinpoint Test B Your best bet , take it to a qualified repair shop

Apr 04, 2017 | 2002 Ford Explorer

1 Answer

99 ford f150 4wd won't engage, clicks but does not engage


Without knowing how the 4X4 works you don't have much chance of finding the problem , (tapping on stuff ) ? There is an electronic control module that makes this system work . Could have DTC'S - diagnostic trouble code's stored in the (GEM)
Transfer Case -Electronic Shift on the Fly (ESOF) Operation The electronic shift on the fly (ESOF) system is an electronic shift 4x4 system that allows the operator to choose between two different 4x4 modes as well as 2-wheel drive. The operator can switch between 2WD and 4H mode at speeds up to 88 km/h (55 mph). To engage or disengage 4L range, the vehicle speed must be less than 5 km/h (3 mph), the brake pedal depressed, and the transmission must be in NEUTRAL.
The transfer case is equipped with an electromagnetic clutch which is located inside the case. This clutch is used to spin up the front driveline when shifting from 2WD to 4H mode at speed. When the control switch on the instrument panel is turned, the generic electronic module (GEM) recognizes that a shift has been requested and activates the electromagnetic clutch and the relays which power the transfer case shift motor. When the shift motor reaches the desired position, as determined by the contact plate position inputs to the GEM, power to the shift relays and motors will be removed. When the transfer case front and rear output shafts are synchronized, the spring loaded lockup collar mechanically engages the mainshaft hub to the drive sprocket. Finally, the front axle collar is engaged and the electromagnetic clutch is deactivated.
Shifts between 2WD and 4H can be made at any speed up to 88 km/h (55 mph). Listed below are the inputs and outputs needed by the GEM to execute a change between any of these modes.
Feature Inputs:
  • 4WD mode switch (various resistances; go to Table 1).
  • Contact plate position inputs A, B, C, D (grounded when closed, open circuit when open; go to Table 4).
Feature Outputs:
  • 4x4 shift motor relay outputs (go to Table 2).
  • Transfer case clutch relay (grounded when relay is activated, open circuit when relay is deactivated).
  • 4x2/4x4 vacuum solenoid (grounded when activated, open circuit when deactivated).
  • Cluster indicators (ground when activated, open circuit when deactivated).
When shifting into or out of 4L, the GEM requires that the vehicle speed be less than 5 km/h (3 mph), the brake is applied, and the transmission is in NEUTRAL.

Feature Inputs:
  • 4WD Mode Switch (various resistances; go to Table 1).
  • Contact Plate Position Inputs A, B, C, D (grounded when closed, open circuit when open; go to Table 4).
  • Output Speed Shaft (OSS) Sensor (Sinusoid Signal: 0.7V-20V, 2.2 Hz/mph).
  • Brake Input (battery voltage when brake is depressed, open circuit when not activated).
  • Transmission Range Sensor (grounded when transmission is in NEUTRAL, open circuit otherwise).
  • Start/Clutch Depressed Input (go to Table 3).
Feature Outputs:
  • 4x4 Shift Motor Relay Outputs (go to Table 2).
  • 4x2/4x4 Vacuum Solenoid (grounded when activated, open circuit when deactivated).
  • Cluster Indicators (grounded when activated, open circuit when deactivated).
  • P1804 Transmission 4-Wheel Drive High Indicator Circuit Failure GEM REFER to Section 413-01A . P1806 Transmission 4-Wheel Drive High Indicator Short Circuit to Battery GEM REFER to Section 413-01A . P1812 Transmission 4-Wheel Drive Mode Select Circuit Failure GEM REFER to the Symptom Chart. P1815 Transmission 4-Wheel Drive Mode Select Short Circuit to Ground GEM REFER to the Symptom Chart. P1820 Transmission Transfer Case Clockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test A . P1822 Transmission Transfer Case Clockwise Shift Relay Coil Short Circuit to Battery GEM GO to Pinpoint Test A . P1824 Transmission 4-Wheel Drive Clutch Relay Circuit Failure GEM GO to Pinpoint Test E . P1826 Transmission 4-Wheel Drive Low Clutch Relay Short Circuit to Battery GEM GO to Pinpoint Test E . P1828 Transmission Transfer Case Counter Clockwise Shift Relay Coil Circuit Failure GEM GO to Pinpoint Test A . P1830 Transmission Transfer Case Counter Clockwise Shift Relay Coil Short Circuit to Battery GEM GO to Pinpoint Test A . P1832 Transmission Transfer Case Differential Lock-Up Solenoid Circuit Failure GEM GO to Pinpoint Test C . P1834 Transmission Transfer Case Differential Lock-Up Solenoid Short Circuit to Battery GEM GO to Pinpoint Test C . P1838 Transmission Transfer Case Shift Motor Circuit Failure GEM REFER to the Symptom Chart. P1846 Transmission Transfer Case Contact Plate 'A' Circuit Failure GEM REFER to the Symptom Chart. P1850 Transmission Transfer Case Contact Plate 'B' Circuit Failure GEM REFER to the Symptom Chart. P1854 Transmission Transfer Case Contact Plate 'C' Circuit Failure GEM REFER to the Symptom Chart. P1858 Transmission Transfer Case Contact Plate 'D' Circuit Failure GEM REFER to the Symptom Chart. P1866 Transmission Transfer Case System Concern - Servicing Required GEM REFER to the Symptom Chart. P1867 Transmission Transfer Case Contact Plate General Circuit Failure GEM REFER to the Symptom Chart. P1876 Transmission Transfer Case 2-Wheel Drive Solenoid Circuit Failure GEM GO to Pinpoint Test C . P1877 Transmission Transfer Case 2-Wheel Drive Solenoid Circuit Short to Battery GEM GO to Pinpoint Test C . P1891 Transmission Transfer Case Contact Plate Ground Return Open Circuit GEM REFER to the Symptom Chart. Your best bet , take it to a qualified repair shop. Tapping on thing's isn't the way to diagnose

Jan 10, 2018 | Cars & Trucks

1 Answer

I have a 98 explorer 4x4 stuck in 4 low. ive tried everything that was sugg. now when i start it iut wont go into gear and when i pit it back into park it makes a loud fast paced ticking sound. i have to...


I'm assuming you have Transfer Case -Automatic Four Wheel Drive (A4WD) An not Transfer Case -All-Wheel Drive (AWD) Two different system's . The automatic system is electroniclly controlled . When it has electrical problems it set DTC'S - diagnostic trouble code's in the 4X4 control module . Before replacing part's or trying this an trying that , having the vehicle checked for DTC'S is always the first step in any diagnostic's with these vehicles . Then if not familiar with this system read factroy service repair information . Trying to fix not knowing what your doing never works .
System Function
Hall effect sensor monitors input and output shaft speed.
In the A4WD (C-Trac) system, the GEM varies the torque sent to the front driveline by controlling the transfer case clutch. At rest and under cruising conditions, the GEM activates the transfer case clutch a minimum duty cycle (percentage of time the clutch is turned on), which allows for the slight difference between the front and rear driveshafts which normally occurs when negotiating a corner on dry pavement. Under any of the following conditions, the GEM will increase the duty cycle in order to prevent or control slip:
  • Slip is detected (by using the Hall Effect Sensors)
  • Heavy acceleration (throttle position).
Feature inputs:
  • Brake ON/OFF switch.
  • 4WD mode switch.
  • Digital transmission range sensor.
  • Clutch switch (manual transmission vehicles only).
  • Vehicle speed signal (transmitted from the ABS module).
  • Front/rear driveshaft speed sensors.
  • Throttle position information from the PCM.
  • Contact plate position inputs A, B, C, D.
Feature outputs:
  • Solid state clutch relay (pulse width modulated signal: grounded when relay is on, battery potential when relay is off).
  • A4WD indicator (ground when activated, open circuit when deactivated).
  • 4x4 shift motor relay outputs.
Shifts between A4WD and 4x4 HIGH can be made at any speed. Listed below are the inputs and outputs needed by the GEM to execute a change between any of these modes.
Feature inputs:
  • Front/rear driveshaft speed sensor.
  • Vehicle speed signal.
  • Throttle position information.
  • 4WD mode switch.
Feature outputs:
  • Solid state clutch relay (pulse width modulated signal; grounded when relay is on, battery potential when relay is off).
  • 4x4 HIGH cluster indicator (ground when activated, open circuit when deactivated).
When shifting into or out of LOW range, the GEM requires that the vehicle speed is less than 5 km/h (3 mph), the brake is applied, and the transmission is in NEUTRAL.
Feature inputs:
  • Throttle position information.
  • 4WD mode switch.
  • Contact plate position inputs A, B, C, D.
  • Vehicle speed signal (transmitted from ABS module).
  • Brake ON/OFF switch input (battery voltage when brake is depressed, open circuit when not activated).
  • Digital transmission range sensor (ground when transmission is in NEUTRAL, open circuit otherwise).
  • Start/clutch depressed input (manual transmission only).
Feature outputs:
  • 4x4 shift motor relay outputs.
  • 4LOW cluster indicators (ground when activated, open circuit when deactivated).
  • Solid state clutch relay (pulse width modulated signal; grounded when relay is on, battery potential when relay is off).
  • The GEM they talk about is a generic electronic control module .
  • Do you know what DTC'S are ?
  • P1763 Transmission Neutral In Tow Indicator Circuit Short to Battery GEM REFER to Section 413-09 . P1764 Transmission Neutral In Tow Indicator Circuit Fault GEM REFER to Section 413-09 . P1804 4WD High Indicator Circuit Failure GEM GO to Pinpoint Test C . P1806 4WD High Indicator Short to Battery GEM GO to Pinpoint Test C . P1808 4WD Low Indicator Circuit Failure GEM GO to Pinpoint Test C . P1810 4WD Low Indicator Short Circuit to Battery GEM GO to Pinpoint Test C . P1812 4WD Mode Select Circuit Failure GEM GO to Symptom Chart. P1815 4WD Mode Select Short Circuit to Ground GEM GO to Symptom Chart. P1820 Transfer Case CW Shift Relay Coil Circuit Open or Short to Ground GEM GO to Pinpoint Test B . P1822 Transfer Case CW Shift Relay Coil Short to Battery GEM GO to Pinpoint Test B . P1824 4WD Electric Clutch Relay Circuit Failure GEM GO to Pinpoint Test A . P1826 4WD Electric Clutch Relay Short to Battery GEM GO to Pinpoint Test A . P1828 Transfer Case CCW Shift Relay Circuit Failure GEM GO to Pinpoint Test B . P1830 Transfer Case CCW Shift Relay Coil Short to Battery GEM GO to Pinpoint Test B . P1836 Transfer Case Front Shaft Speed Sensor Circuit Failure GEM GO to Symptom Chart. P1837 Transfer Case Rear Shaft Speed Sensor Circuit Failure GEM GO to Symptom Chart. P1838 Transfer Case Shift Motor Circuit Failure GEM GO to Pinpoint Test B . P1846 Transfer Case CONTACT PLATE "A" Circuit Failure GEM GO to Pinpoint Test B . P1850 Transfer Case CONTACT PLATE "B" Circuit Failure GEM GO to Pinpoint Test B . P1854 Transfer Case CONTACT PLATE "C" Circuit Failure (GEM Only) GEM GO to Pinpoint Test B . P1858 Transfer Case CONTACT PLATE "D" Circuit Failure (GEM Only) GEM GO to Pinpoint Test B . P1866 Transfer Case Maintenance Required (GEM Only) (4-wheel drive operation can be restored by clearing the DTC and cycling the ignition.) GEM GO to Pinpoint Test B . P1867 Transfer Case Contact Plate General Circuit Failure (GEM Only) GEM GO to Pinpoint Test B . P1874 Automatic Hall Effect Sensor Power Circuit Failure GEM GO to Symptom Chart. P1875 Automatic Hall Effect Sensor Power Circuit Short to Battery (GEM Only) GEM GO to Symptom Chart. P1891 Transfer Case Contact Plate Ground Return Open Circuit GEM GO to Pinpoint Test B .
  • Your best bet , have it towed to a qualified repair shop . You have not the knoweldge or diagnostic equipment to fix it.

Jan 01, 2018 | 1998 Ford Explorer

1 Answer

Ford Explorer wipers, power windows, doom lights won't work


Are u assuming the GEM module is at fault ? Did you or your local auto electrician check for DTC'S - diagnostic trouble codes?
GEM/CTM Wiggle Test Diagnostic Trouble Code (DTC) Index DTC Description DTC Caused By B1317 Battery Voltage HIGH GEM/CTM B1318 Battery Voltage Low GEM/CTM B1322 Driver Door Ajar Circuit Short to Ground GEM/CTM B1330 Passenger Door Ajar Short to Ground GEM/CTM B1352 Ignition Key-In Circuit Failure GEM/CTM B1410 Driver Power Window Motor Circuit Failure GEM B1438 Wiper Mode Select Switch Circuit Failure GEM/CTM B1441 Wiper Mode Select Switch Short to Ground GEM/CTM B1446 Wiper Park Sense Circuit Failure GEM/CTM B1450 Wiper/Wash Interval Delay Switch Input Circuit Failure GEM/CTM B1453 Wiper/Wash Interval Delay Switch Input Short to Ground GEM/CTM B1462 Seat Belt Switch Circuit Failure GEM/CTM B1577 Park Lamp Input Circuit Short to Battery GEM/CTM B1610 Illuminated Entry Input (From RAP Module) Circuit Short to Ground GEM/CTM
Did you an your auto electrican check power an grounds for the GEM ? Voltage drop testing ? . Did you check power an ground circuits for the affected systems . Working when they want sounds more like a loose connection somewhere .
ECM Inputs and Outputs Diagnosis
Symptom Chart
Symptom Chart Condition Possible Sources Action
  • The Wipers Are Inoperative
  • CJB Fuse 16 (30A).
  • Circuitry.
  • GEM/CTM.
  • Multi-function switch (13K359).
  • Wiper run/park relay.
  • Wiper HI/LO relay.
  • Wiper motor.
  • DTC B1431.
  • DTC B1432.
  • DTC B1438.
  • DTC B1450.
  • DTC B1840.
  • GO to Pinpoint Test A .

Plus looking at GEM scan data on a factory scan tool .Too many people miss diagnose these system's because they don't have a clue .

Jul 03, 2017 | 1999 Ford Explorer

2 Answers

None of my power windows on 1998 Mercury Mountaineer work, checked fuses but can't find power relay if there is one. Any suggestions


If you checked the fuses and they are fine, try this. With the key on and the window button down or up, open and close the door holding in the up or down position. If the window moves, there is a wire(s) are broken in the wire harness that goes from the door jam to the door. This is a common problem that we find with window and door operating problems. You may find 1 bad or broken wire, or 4-5 broken wires. Let us know if this help you find a repair, for this concern. Craig

Jan 23, 2010 | 1998 Mercury Mountaineer

2 Answers

4wd does not work


Electronic Shift On the Fly (ESOF) Operation
The ESOF system is an electronic shift 4x4 system that allows the operator to choose between two different 4x4 modes as well as 2-wheel drive. The operator can switch between 2WD and 4WD HIGH mode at speed. To engage or disengage LOW Range, the vehicle speed must be less than 5 kph, the brake depressed, and the transmission must be in NEUTRAL.

The transfer case is equipped with an electromagnetic clutch which is located inside the case. This clutch is used to spin up the front drive-line when shifting from 2WD to 4x4 High mode at speed. When the control switch on the instrument panel is turned, the generic electronic module (GEM) recognizes that a shift has been requested and activates the electromagnetic clutch and the relays which power the transfer case shift motor. When the shift motor reaches the desired position as determined by the contact plate position inputs to the GEM, power to the shift relays and motors will be removed. When the transfer case front and rear output shafts are synchronized, the spring loaded lockup collar mechanically engages the main-shaft hub to the drive sprocket. Finally, the front axle collar is engaged and the electromagnetic clutch is deactivated.

Shift Between 2WD and 4x4 HIGH:
Shifts between 2WD and 4x4 HIGH can be made at speed. Listed below are the inputs and outputs needed by the GEM to execute a change between any of these modes.

Feature Inputs:
*4WD Mode Switch (Various resistances).
*Contact Plate Position Inputs A, B, C, D (grounded when closed, open circuit when open).

Feature Outputs:
*4x4 Shift Motor Relay Outputs
*Transfer Case Clutch Relay (grounded when relay is on, open circuit when relay is off).
*4x2/4x4 Vacuum Solenoid (grounded when activated, open circuit when deactivated).
*Cluster Indicators (ground when activated, open circuit when deactivated).

Shifting Into/Out of 4WD LOW:
When shifting into or out of 4WD LOW, the GEM requires that the vehicle speed be less than 5 kph, the brake is applied, and the transmission is in NEUTRAL.

Feature Inputs:
*4WD Mode Switch (Various resistances).
*Contact Plate Position Inputs A, B, C, D (grounded when closed, open circuit when open).
*VSS Sensor (Sinusoid Signal: 0.7V-20V, 2.2 Hz/mph).
Brake Input (battery voltage when brake is depress, open circuit when not activated).
*Transmission Range Sensor (grounded when transmission is in NEUTRAL, open circuit otherwise).
8Start/Clutch Depressed Input

Feature Outputs:
*4x4 Shift Motor Relay Outputs
*4x2/4x4 Vacuum Solenoid (grounded when activated, open circuit when deactivated).
*Cluster Indicators (grounded when activated, open circuit when deactivated).

4WD Mode Switch
A rotary switch allows the vehicle operator to choose between 2WD, 4WD HIGH, and 4WD LOW modes of 4x4 operation.

GEM Module
The Generic Electronic Module (GEM) controls the operation of the 4x4 system

Vehicle Speed Sensor
The vehicle speed sensor (VSS), mounted in the rear of the transfer case, informs the GEM of the vehicle speed.

Transfer Case Shift Motor Sense Plates

The shift motor sense plate, an integral part of the electric shift motor, informs the GEM to the positions of the transfer case

Transmission Range Sensor
Located on the left side of the transmission, this sensor informs the GEM when the transmission is in the NEUTRAL position.

Electric Shift Motor
The electric shift motor, mounted externally at the rear of the transfer case, drives a rotary cam which moves the mode fork and range fork within the transfer case to select between the 2WD, 4WD HIGH, and 4WD LOW positions.

4x4/4x2 Vacuum Solenoids
These two solenoids are attached to the upper RH side of the engine compartment dash, and alternately route vacuum to the vacuum motor which engages/disengages the center axle disconnect collar in the front axle assembly.

4x4 Shift Motor Relay
A module containing two relays which under the control of the GEM, shift the transfer case shift motor between the 2WD, 4WD HIGH, and 4WD LOW modes.

Transfer Case Clutch Relay
An electromechanical relay is used to activate the transfer case clutch within the transfer case.

Good luck and hope this helps,but start with the simple and check the fuses and wire harness. Both white/light blue stripe wires should have 12V in run. The GEM will ground the left side (closest to engine) solenoid to disengage the front axle. It will ground the the right side solenoid (closest to fender) to engage the front axle. If the GEM doesn't see Neutral it will not let the truck come out of 4Lo. If the GEM had water leaking on it it may well be the root of the problem. The shift motor only has power when the GEM sends it a signal to move the shift lever. Once the shift is completed the motor shuts off. There are 2 wires that control the shift motor. A yellow and an orange. The GEM alternates between 12v and Ground to these wires to control which way the motor turns. The GEM uses the transfer case shift relay module to control the power to the motor. There are contact plates inside the shift motor assembly that indicate the position that the shift lever is in. This is what the GEM used to know what the T-case is doing. Any one of these components can fail.







Jan 10, 2010 | 2002 Ford Explorer

2 Answers

Door panel lights wont turn off


push the door switches in by hand and see if the lights go out. Here's some diagnostic info:

Vehicles may be equipped with either a generic electronic module (GEM) or a central timer module (CTM) depending on vehicle options.
  • Vehicles with 4-wheel drive or the power group option will be equipped with a GEM.
  • Vehicles with 2-wheel drive and no power group option will be equipped with a CTM.
Courtesy Lamps The GEM and the CTM illuminate the interior lamps when any door is open or ajar. The interior lamps are: the interior lamp, the cargo lamp and the door courtesy lamp. The courtesy lamps will shut off when:
  • The doors are closed and the illuminated entry (GEM only) feature is not active.
  • The vehicle speed is greater than 15 mph (24 km/h). The interior lamps will not be reactivated until the vehicle speed is less than 10 mph (16 km/h) and a new door open warning lamp switch signal is received (GEM only).
The system inputs to the GEM/CTM are as follows:
  • The door open warning lamp switches. (Grounded when door is ajar; an open circuit when the door is closed.)
  • The vehicle speed sensor (VSS) input. (Sinusoid Wave: 0.7V-20V, 2.2 Hz/MPH [1.37 Hz/km/h] [GEM only].)
The system output to the GEM/CTM is as follows:
  • The interior lamp relay coil output. (Grounded when activated; open circuit when deactivated.)
Interior Lamp Relay The GEM and the CTM control the interior lamps and illuminated entry function with the interior lamp relay.
The relay is activated by applying ground to the relay coil through GEM C267-15, and is deactivated by removing the ground signal.
Panel Dimmer Switch The panel dimmer switch is integrated into the headlamp switch and controls the interior lamps by activating the interior lamp relay.
Illuminated Entry (GEM Only) The GEM illuminates the interior lamps when an unlock signal is received from the remote anti-theft personality (RAP) module. The illuminated entry feature will be canceled when any of the following conditions are met:
  • 25 seconds have elapsed since the illuminated entry feature was activated and the courtesy lamp feature is not activated.
  • The GEM receives a request from the RAP module (remote transmitter lock button pressed) and the courtesy lamp feature is not activated.
  • The ignition is in the RUN or START position and the courtesy lamp feature is not activated.
The illuminated entry inputs are:
  • RAP illuminated entry request. (Grounded pulse of varying length.)
  • Ignition switch in the RUN position. (Battery voltage on both the RUN and RUN/ACC inputs.)
The illuminated entry outputs are:
  • Interior lamp relay coil output. (Grounded when activated; an open circuit when deactivated.)
RAP Module The RAP module sends a signal to the GEM on the illuminated entry request circuit to indicate a request to turn the illuminated entry feature on or off. Circuit 1013 (BR/LG) is normally sent 12 volts by the GEM. The RAP module shorts this circuit to ground with a pulse of either of the following lengths:
  • 200 ms pulse from RAP receiver assembly requests illuminated entry ON (unlock button pressed).
  • 300 ms pulse from RAP receiver assembly requests illuminated entry OFF (lock button pressed).
GEM Sleep Mode The GEM and the CTM sleep mode deactivate all outputs to conserve battery power. Sleep mode is entered when the ignition has not entered the RUN or ACC position and 45 minutes has elapsed since the last wake-up input was received. In this mode, GEM current consumption is reduced to 5.0 mA or less. During sleep mode the GEM monitors the following wake-up inputs:
  • Both front door open warning lamp switches.
  • Ignition switch in the key-in, ACC and RUN position.
  • RAP illuminated entry request.
The GEM sleep mode outputs are:
  • None. (All circuits are deactivated during sleep mode.)
If a change in any of the above inputs occur while the GEM is asleep, the GEM will wake up and monitor all of its inputs and have the ability to activate any of its outputs.
The following components are under the control of the battery saver relay:
  • Interior lamp.
  • Engine compartment lamp.
  • Glove compartment lamp.
  • Panel dimmer switch.
  • Interior lamp relay.
The battery saver relay becomes active (relay coil is energized) when the GEM is in the awake mode, and is deactivated (relay coil is de-energized) in the sleep mode. The battery saver will remain active until the ignition switch is removed from the ACC or RUN position and 45 minutes have passed since the last active input was received (see sleep mode inputs). At that time, the relay will be deactivated and power to the above circuits will terminate.
The battery saver inputs are the GEM sleep mode inputs.
The battery saver output is the battery saver relay.
Inspection and Verification — GEM/CTM
  1. The interior lighting system is a generic electronic module (GEM)/central timer module (CTM) controlled system. Refer to Section 419-10 for additional information regarding GEM/CTM diagnostic strategies.
  1. Verify the customer concern by operating the interior lamps.
  1. Visually inspect for obvious signs of mechanical and electrical damage.


Visual Inspection Chart Mechanical Electrical
  • Switch(es)
  • Fuse(s) 14 (15A), 15 (5A), 4 (5A), 8(5A), and 103 (50A).
  • Wiring harness
  • Loose or corroded connector(s)
  • Circuitry open/shorted
  • Bulb(s)

  1. If the concern remains after the inspection, connect the New Generation STAR (NGS) Tester to the data link connector (DLC) located beneath the instrument panel, and select the vehicle to be tested from the NGS menu. If the NGS does not communicate with the vehicle:
    • check that the program card is correctly installed.
    • check the connections to the vehicle.
    • check the ignition switch position.

Oct 07, 2009 | 1999 Ford F250 Regular Cab

1 Answer

Time delay relay for interior lights


I would suspect you have a bad door switch on one of the doors or liftgate. They are usually plunger switches. Try pusing them in one at a time and see f the lights go out. Hold it in long enough to account for the time delay.

please rate if this helps you.

---------
  • The Courtesy Lamps Stay On Continuously
  • Circuitry.
  • GEM/CTM.
  • Ignition switch.
  • Interior lamp relay.
  • Dimmer module.
  • Door ajar switch.
  • DTC B1322.
  • DTC B1330.
  • DTC B1334.
  • DTC B1338.
  • DTC B1371.
  • DTC B1574.
  • DTC B1610.


------------------------------------
Generic Electronic Module (GEM)/Central Timer Module (CTM) Controlled Functions
The generic electronic module (GEM) is equipped on four-wheel drive vehicles with power windows. The central timer module (CTM) is equipped only on two-wheel drive vehicles without power windows.
NOTE: GEM/CTM diagnostics are compatible with New Generation STAR (NGS) Tester.
The GEM/CTM incorporates the functions of several different modules into one, and offers diagnostics to easily locate and repair concerns affecting the subsystems that it controls.
The GEM/CTM constantly monitors the systems under its control and reports a concern in the form of a diagnostic trouble code (DTC). A DTC can be retrieved with NGS Tester through the communication link.
NGS Tester is a menu-driven tester that allows the user to run specific tests. NGS Tester can isolate faults in the GEM/CTM subsystems through a symptom-driven diagnostic procedure. Connecting NGS Tester to the GEM/CTM communication link will not alert the GEM/CTM. If the GEM/CTM is "asleep" when the diagnostic connector is plugged in, the GEM/CTM must be "awakened". If the communication link cannot be established, it is advised to turn the ignition to RUN.
NOTE: The GEM/CTM has a sleep function to minimize battery consumption. During the sleep mode, the GEM/CTM turns off all outputs and monitors only the following:
  • Door ajar (driver door, passenger door, liftgate, LH rear and RH rear doors).
  • Key-in-ignition.
  • Key in RUN or ACC.
  • Two-step unlock switch (unarm switch).
  • Digital TR sensor.
  • Illuminated entry request (remote anti-theft personality [RAP] module).
If a change of status occurs at one of these inputs while the GEM/CTM is asleep, the GEM/CTM will "wake up." When the GEM/CTM awakens, it performs an internal self-test, and begins normal operation. At this point, the GEM/CTM will have all of its functions operational.
The GEM/CTM will go into the sleep mode immediately after both of the following conditions have been met:
  • Key in OFF or key not in ignition.
  • After 45 minutes with no change in any wake-up input.
The GEM/CTM control system has two modes of operation; the normal operating mode and the tester-dependent diagnostics mode.
The normal operation of the GEM/CTM can detect errors. An integral part of the normal GEM/CTM operation is the continuous diagnostic capability. Continuous diagnostics detects errors and changes the GEM/CTM control strategy. There is no warning lamp for the GEM/CTM; therefore, a DTC concern will direct you to the GEM/CTM. Examples of faults that may be detected during normal operation include:
NOTE: The GEM/CTM can only detect open circuit/short to GRD faults when the GEM/CTM in not energizing a load, and short to battery faults when the GEM/CTM is attempting to energize a load.
  • GEM/CTM continuous self-test (RAM, ROM, EEPROM, A/D checking).
  • Output driver monitoring (open circuit/short to ground [GRD], short to power).
  • Illogical combinations of input signals.

Apr 28, 2009 | 1998 Ford Explorer

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