Question about 2001 Ford Explorer Sport Trac

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My 4wd will not work. I replaced the transfer case, the motor, and the switch. The light does not come on but you can hear the clicking noise in the dash. I give up! What can I do to troubleshoot and see what the actual problem is.

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Is the light just not working? Are you sure that the 4 wheel drive at the wheels is not working? ie does only your right rear wheel spin on ice and snow?
If you are sure of all the previous things then you need to make sure there is power going to the transfer case motor when you activate the switch. If no power it could be a fuse or relay causing the problem.

Posted on Oct 31, 2012

  • 1 more comment 
  • Tiffany Oct 31, 2012

    How would I see if there is power going to the transfer case motor?

  • donitarenzo7
    donitarenzo7 Oct 31, 2012

    you can use a test light to see if you are getting power to your shift actuator by unplugging actuator and testing for power at your wires while someone activates your switch

  • Tiffany Apr 10, 2013

    well after all I put into it, the computer was actually bad. 4 wheel drive working great!



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Posted on Jan 02, 2017

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SOURCE: 2000 explorer xlt stuck in 4wd hi

if you are testing the voltage at the mtr on the tansfer case and you have voltage all other parts are working . so that leaves two things the mtr our the coller that engauges our disengauges the tansfer case you are almost there in solving your problem good luck kdc744

Posted on Jan 27, 2009

  • 5 Answers

SOURCE: 2001 f250 won't shift into 4wd high using the dash

you can use a test light to see if you are getting power to your shift actuator by unplugging actuator and testing for power at your wires while someone activates your switch,if you have power then should be a bad actuator.

Posted on Feb 25, 2009

  • 984 Answers

SOURCE: 2003 Ford F-150 4WD is not working. Light does not

Which type is it, ESOF ( Electronic Shift on the Fly ) or MSOF ( Mechanical Shift on the Fly ) ?

Best to check by jacking the truck up ( taking safety precautions, parking brake, chock the wheels, jack stands, etc ), turn the key to the run position and place into 4WD.
If the front drive shaft turns, the problem is in the transfer case.
If the front drive shaft does not turn, the problem is in the front axle.

I would suspect the front shaft does not turn, and the most common cause of this is the vacuum motor on the front axle, the vacuum lines to it, or the vacuum solenoids.
The vacuum shift motor is what locks the front wheels in, and without this action, the PM does not get the confirm that the truck is good to go, and illuminate the cluster indicators ( 4x4, and if 4L the Low Range lamps ).
There are 2 vacuum solenoids, one is 4WD one is 2WD ( to move the motor one way or the other ).
Start with checking for vac on the vacuum motor ( actually it is a diaphragm ). The pink line should have vacuum when in 4WD, the blue line should have vacuum when in 2WD. If not, time to work back towards the solenoids. Use a short length of hose on the vacuum solenoids, and retest.
If still missing vacuum on the 4WD solenoid, I would suspect it is bad, but best to test on the other side of it, to make sure the vacuum reservoir ( mounted behind the battery box ) is supplying vacuum to the solenoids.

This is just the most common cause, best to confirm with the 1st test above, to know if you should look to the trans case, or axle.

This is what the vacuum shift motor looks like on the front axle

These are the vacuum shift solenoids

Posted on Dec 12, 2009

  • 474 Answers

SOURCE: 2002 Ford Explorer 4WD. 4WD is inopertive.

put a ground strap from your transfer case to your transmission. also with someone listening under the car with the key on but not running put your foot on the brake, shift to neutral and turn the selecter to 4x4 low and see if you can hear the actuater respond

Posted on Dec 19, 2009

  • 3854 Answers

SOURCE: 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.

Posted on Jan 10, 2010

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