Starting problem, where is open circuit relay located

P1235 - Fuel Pump Control Out Of Range Note: For LS6/LS8 and Thunderbird, the FPDM functions are incorporated in the Rear Electronics Module (REM). Also, the REM does not use a FPM circuit. Diagnostic information will be sent through SCP.
P1235 indicates that the FPDM has detected an invalid or missing FP circuit signal from the PCM. The FPDM will send a message to the PCM through the FPM circuit, indicating that this failure has been detected. The PCM will set the DTC when the message is received.

• FP circuit open or shorted
• Electronic Throttle Control (ETC) system concern (check for ETC DTC P2105).
• Damaged FPDM.
• Damaged PCM

• The FPDM sends a 25% duty cycle (250 msec ON, 750 msec OFF) through the FPM circuit to the PCM while the fault is being detected by the FPDM. If the fault is no longer detected, the PDM will return to sending an "all OK" (50% duty cycle) message to the PCM. The PCM will keep P1235 stored in Continuous Memory.
• For LS6/LS8 and Thunderbird, check if Electronic Throttle Control (ETC) DTC P2105 is present. An ETC system concern could cause a P1235, and should be diagnosed first.

KB1 DTC P1233 OR P1234: IS DTC P1233 OR P1234 PRESENT IN KEY ON ENGINE OFF SELF TEST Is DTC P1233 or P1234 present in Key On Engine Off Self-Test?
Yes No A hard fault is present. GO to KB2 . The PCM is now receiving a signal from the FPDM. One possible cause of the DTC P1233 or P1234 is that the IFS switch was tripped, then reset.

If engine is now a no start:

Disregard the DTC P1233 or P1234 at this time. RETURN to Section 3 and CONTINUE as directed. After servicing the no start, to diagnose intermittent causes of the DTC P1233 or P1234, RETURN to GO to KB25 .

If engine will start:

GO to KB25 to diagnose intermittent condition. KB2 DOES THE ENGINE START? Does the engine start?
Yes No GO to KB15 (to check the FPM circuit). VERIFY IFS switch is set (button depressed). If OK, GO to KB3 . KB3 CHECK POWER AND GROUND CIRCUITS TO FPDM

• Disconnect FPDM.
• Key on, engine off.
• Measure voltage between the FPDM PWR pin and ground pin at the FPDM harness connector.

Is voltage greater than 10.5 volts?



Yes No Key off. REPLACE FPDM. GO to KB4 . KB4 CHECK POWER TO FPDM

• Key on, engine off.
• Measure voltage between the FPDM PWR pin at the FPDM harness connector and chassis ground.

Is voltage greater than 10.5 volts?



Yes No REPAIR open ground circuit to FPDM. KEY OFF. No power to FPDM.

For Escort, Mustang:

GO to KB5 .

All Others:

GO to KB8 . KB5 CHECK B+ VOLTAGE TO CCRM PIN 11 (FPDM POWER SUPPLY RELAY)

• Disconnect CCRM.
• Measure B+ circuit voltage at Pin 11 of the CCRM harness connector.

Is voltage greater than 10.5 volts?
Yes No For Mustang:

GO to KB6 .

For Escort:

GO to KB7 . VERIFY integrity of related fuse. If OK, REPAIR open B+ circuit. If fuse is damaged, CHECK B+ and FPDM PWR circuits for short to ground before replacing. KB6 CHECK GROUND CIRCUIT TO CCRM PIN 18

• Measure resistance of ground circuit between CCRM harness connector Pin 18 and chassis ground.

Is resistance less than 5.0 ohms?
Yes No GO to KB7 . SERVICE open ground circuit. KB7 CHECK FOR OPEN FPDM PWR CIRCUIT

• Measure resistance of FPDM PWR circuit between CCRM harness connector (pin 5) and FPDM harness connector.

Is resistance less than 5.0 ohms?
Yes No REPLACE CCRM. The FPDM PWR circuit is open. GO to KB13 to help isolate fault. KB8 CHECK B+ VOLTAGE TO FPDM POWER SUPPLY RELAY

• Disconnect FPDM power supply relay.
• Measure B+ circuit voltage at the FPDM power supply relay harness connector.

Is voltage greater than 10.5 volts?
Yes No GO to KB9 . VERIFY integrity of related fuse. If OK, REPAIR open B+ circuit. If fuse is damaged, CHECK B+ and FPDM PWR circuits for short to ground before replacing. KB9 CHECK FOR GROUND TO FPDM POWER SUPPLY RELAY

• Disconnect scan tool from DLC.
• Measure resistance of ground circuit between FPDM power supply relay harness connector and battery negative post.

Is resistance less than 5.0 ohms?
Yes No GO to KB10 . REPAIR open circuit. KB10 CHECK FOR OPEN FPDM PWR CIRCUIT

• Measure resistance of FPDM PWR circuit between FPDM power supply relay harness connector and FPDM harness connector.

Is resistance less than 5.0 ohms?
Yes No RECONNECT FPDM. GO to KB11 . The FPDM PWR circuit is open. GO to KB13 to help isolate fault. KB11 CHECK VPWR CIRCUIT VOLTAGE (IGN START/RUN for Taurus/Sable) TO FPDM POWER SUPPLY RELAY

• Key on, engine off.
• Measure VPWR circuit voltage (IGN START/RUN for Taurus/Sable) at the FPDM power supply relay harness connector.

Is voltage greater than 10.5 volts?
Yes No REPLACE FPDM power supply relay. REPAIR open VPWR (or IGN START/RUN) circuit. KB13 ISOLATE OPEN IN FPDM PWR CIRCUIT

• Disconnect IFS switch.
• Measure resistance of FPDM PWR circuit between IFS switch harness connector and FPDM power supply relay harness connector (for Escort and Mustang, CCRM harness connector [pin 5]).
• Measure resistance of FPDM PWR circuit between FPDM harness connector and IFS switch harness connector.

Are both resistances less than 5.0 ohms?
Yes No VERIFY that the IFS switch is set (button depressed). If OK, REPLACE IFS switch. REPAIR open in appropriate area of FPDM PWR circuit. KB15 CHECK FOR OPEN FPM CIRCUIT

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect FPDM.
• Disconnect PCM.
• Measure resistance of FPM circuit between PCM harness connector and the FPDM harness connector.

Is resistance less than 5.0 ohms?
Yes No GO to KB16 . REPAIR open circuit. KB16 CHECK FPM CIRCUIT FOR SHORT TO POWER IN HARNESS

• Key on, engine off.
• Measure voltage between FPM circuit at the PCM harness connector and ground.

Is voltage less than 1.0 volt?
Yes No KEY OFF. GO to KB17 . REPAIR short circuit. KB17 CHECK FPM CIRCUIT FOR SHORT TO GROUND IN HARNESS

• Disconnect scan tool from DLC.
• Measure resistance between FPM circuit at the PCM harness connector and ground.

Is resistance greater than 10,000 ohms?
Yes No GO to KB18 . REPAIR short circuit. KB18 CHECK FOR FPM OUTPUT FROM FPDM

• Reconnect FPDM.
• Key on, engine off.
• Measure dc voltage between FPM circuit at the PCM harness connector and ground.

Is voltage between 0.02 and 1.0 volt dc? (It is OK for the voltage to cycle below this range and then return to within range.)
Yes No REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) ). REPLACE FPDM. KB25 CHECK CIRCUITS THAT MAY CAUSE AN INTERMITTENT LOSS OF POWER SUPPLY TO THE FPDM. ALSO CHECK FOR INTERMITTENT OPENS OR SHORTS ON THE FPM CIRCUIT.

Note: Be aware that P1233/1234 could be set if the inertia fuel shutoff (IFS) switch was tripped then reset.


Your best bet , take it to a qualified repair shop.

C1123 Vehicle Speed Circuit Fault Overhead Console Module REFER to Section 413-08 .

The body control module (BCM) controls the park lamp relay by grounding the control circuit of the park lamp relay when the headlamp switch is turned to the PARK or the HEAD position. This energizes the park lamp relay, illuminating the park lamps.

• If the DTC B2587 is a history DTC, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
• An intermittent short to ground or an open in the following locations may cause an intermittent malfunction to occur:
- The control circuit of the park lamp relay
- The park lamp relay
- The BCM
Step
Action
Yes
No
Schematic Reference: Exterior Lights Schematics
Connector End View Reference: Master Electrical Component List
1
Did you perform the Diagnostic System Check?
YES - Go to Step 2
NO - Go to Diagnostic System Check - Lighting Systems
2
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With a scan tool, command the park lamp relay ON and OFF.
Does the park lamp relay turn ON and OFF with each command?
YES - Go to Diagnostic Aids
NO - Go to Step 3
3
Turn OFF the ignition.
Disconnect the park lamp relay.
Turn ON the ignition, with the engine OFF.
Connect a test lamp between the battery voltage circuit of the park lamp relay coil and ground.
Does the test lamp illuminate?
YES - Go to Step 4
NO - Go to Step 10
4
Connect a test lamp between the control circuit of the park lamp relay and the battery voltage circuit of the park lamp relay coil.
With a scan tool, command the park lamp relay ON and OFF .
Does the test lamp turn ON and OFF with each command?
YES - Go to Step 8
NO - Go to Step 5
5
Does the test lamp remain illuminated with each command?
YES - Go to Step 7
NO - Go to Step 6
6
Test the control circuit of the park lamp relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 13
Go to Step 9
7
Test the control circuit of the park lamp relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 13
Go to Step 9
8
Inspect for a poor connection at the park lamp relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 13
Go to Step 11
9
Inspect for a high resistance or a poor connection at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 13
Go to Step 12
10
Replace the underhood fuse block. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Did you complete the repair?
Go to Step 13
--
11
Replace the park lamp relay. Refer to Relay Replacement in Wiring Systems.
Did you complete the replacement?
Go to Step 13
--
12
Important: Perform the set up procedure for the body control module (BCM). Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control Systems.
Replace the BCM. Refer to Body Control Module Replacement in Body Control System.
Did you complete the replacement?
Go to Step 13
--
13
Use the scan tool in order to clear the DTCs .
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?
Go to Step 2
System OK

Will not start how intermittently ? The engine won't turn over or engine does turn but won't start . Starter relay , lose connection . Checking power an grounds would be the first place to start , voltage drop test the main electrical circuits . Voltage Drop Testing the Starter

The starter circuit control is achieved by the starter motor relay ! It is located in the under hood fuse/ relay box or as Chrysler calls it ,integrated power module ! If you pull out the relay an look on the bottom where the pins stick out you will see four sets of numbers .30,87 an 85,86 ! 30 is B+ voltage . 87 is to the starter solenoid . If you jumped those two spots where the relay plugs into the starter would crank the engine over . The last two 85 an 86 are the control side .If you checked with a volt meter where 86 plugged into ,with key on it would show B+ voltage . The last pin is from the PCM - engine computer . When turning the key to start a signal is sent to the PCM to let it know crank has been requested , in return the PCM supplies a ground to pin 85 energizing the starter motor relay sending B+ voltage to the starter motor cranking over the engine . Here is another video on test from the relay base (where relay plugs into ) This is for a horn circuit but same thing . VEHICLE RELAYS Testing from the relay base The relay could be going bad , you never know .Replacing the relay mite not be a bad idea . Good luck , hope this helps !

DTC P1599 will set if the PCM has detected an engine stall condition when:
?€¢
The engine is in run mode.

?€¢
Ignition voltage is present on circuit 839.

?€¢
The CKP signal at PCM is NOT detected.

DTC P1599 is a type D DTC
The PCM has the ability to set a diagnostic trouble code (DTC) if the engine stalls when the ignition has NOT been turned OFF. This DTC may aid in intermittent diagnosis of a customer complaint of intermittent engine stall. The scan tool Failure Record information can be duplicated under the same stall conditions in an attempt to reproduce the occurrence. Since DTC P1599 is a type D DTC, the PCM will not command the MIL or SERVICE telltale ON. This DTC can set due to driver error. For example, a vehicle equipped with a manual transaxle in which the clutch was released too quickly causing the engine to stall.
DTC P1640 (PCM Output Circuit)
The PCM contains an output driver module (ODM) which controls 7 circuits: A/C relay, air pump relay, EVAP purge solenoid, EVAP vent solenoid, fan control 1, fan control 2, and TCC solenoid. The ODM controls each of these circuits independently by controlling the circuit ground. The ODM monitors the voltage level at each of the 6 circuits into the PCM when the device is being commanded ON or OFF. When the device is commanded OFF, the circuit is not grounded, the voltage level at the PCM should be high (ignition voltage). When the device is commanded ON, the circuit is grounded, the voltage level at the PCM should be low. Each of the 7 drivers in the ODM contains a feedback circuit used to determine if a particular circuit failed, which can be read on the scan tool. DTC P1640 sets when any one of the 7 feedback voltages is low when that device is turned OFF or when any one of the 7 feedback voltages is high when that device is turned ON when the engine is running.
Sounds to me like you have a short on one of these circuits !
To locate an intermittent problem, use the scan tool to command each of the 7 solenoids tied to the ODM circuit ON and OFF independently while monitoring:
A/C RELAY CKT OPEN SHORT TO GND
A/C RELAY CKT SHORT TO VOLTS
OR
AIR PUMP REL. CKT OPEN SHORT TO GND
AIR PUMP REL. CKT SHORT TO VOLTS
OR
EVAP PURGE CKT OPEN SHORT TO GND
EVAP PURGE CKT SHORT TO VOLTS
OR
EVAP VENT CKT OPEN SHORT TO GND
EVAP VENT CKT SHORT TO VOLTS
OR
FC 1 RELAY CKT OPEN SHORT TO GND
FC 1 RELAY CKT SHORT TO VOLTS
OR
FC 2 RELAY CKT OPEN SHORT TO GND
FC 2 RELAY CKT SHORT TO VOLTS
OR
TCC DUTY CYCLE OPEN SHORT TO GND
TCC DUTY CYCLE SHORT TO VOLTS
If IGN 3 fuse is open, A/C RELAY CKT OPEN SHORT TO GND, EVAP VENT CKT OPEN SHORT TO GND, and EVAP PURGE CKT OPEN SHORT TO GND parameters on the scan tool will read YES.
Do you have a DVOM - digital volt ohm meter ? You need to check each wire in the above circuits for a short to ground or B+ !

More then likely you have a bad ground wire. You will have to start tracing this problem back to find the issue. Other issue is a intermittent power wire shorting

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_677dced97ad9bddf

94+ AIR BAG DIAGNOSTIC TROUBLE CODES/CLEARING
Code Component/Fault Description

No Air Bag Indicator - Inoperative Indicator Circuit
Continuous Air Bag Indicator - Diagnostic Trouble Code Timed Out, Diagnostic Monitor Disconnected or Inoperative, or No Ignition Voltage to Diagnostic Monitor.
12 Lost Battery Feed
13 Air Bag Circuit Shorted to Ground
14 Primary Crash Sensor Circuit Shorted to Ground
21 Diagnostic Monitor Not Mounted to Vehicle Properly
22 Safing Sensor Output Circuit Shorted to Battery Voltage
23 Memory Clear Circuit Improperly Grounded
24 System Disarm Failure or Internal Diagnostic Monitor Fault
32 Driver Side Air Bag Circuit High Resistance or Open
33 Passenger Side Air Bag Circuit High Resistance or Open
34 Driver Side Air Bag Circuit Low Resistance or Shorted
35 Passenger Side Air Bag Circuit Low Resistance or Shorted
41 RH Radiator Primary Crash Sensor Feed/Return Circuit Open
42 LH Radiator Primary Crash Sensor Feed/Return Circuit Open
44 RH Radiator Primary Crash Sensor Not Mounted to Vehicle Properly
45 LH Radiator Primary Crash Sensor Not Mounted to Vehicle Properly
52 Intermittent or Repaired Lost Battery Feed
53 Intermittent or Repaired Air Bag Circuit Shorted to Ground
54 Intermittent or Repaired Primary Crash Sensor Circuit Shorted to Ground
61 Intermittent or Repaired Diagnostic Monitor Not Mounted to Vehicle Properly
62 Intermittent or Repaired Safing Sensor Output Circuit Shorted to Battery Voltage
63 Intermittent or Repaired Memory Clear Circuit Improperly Grounded
64 Intermittent or Repaired System Disarm Failure or Internal Diagnostic Monitor Fault
72 Intermittent or Repaired Driver Side Air Bag Circuit High Resistance or Open
73 Intermittent or Repaired Passenger Side Air Bag Circuit High Resistance or Open
74 Intermittent or Repaired Driver Side Air Bag Circuit Low Resistance or Shorted
75 Intermittent or Repaired Passenger Side Air Bag Circuit Low Resistance or Shorted
81 Intermittent or Repaired RH Radiator Primary Crash Sensor Feed/Return Circuit Open
82 Intermittent or Repaired LH Radiator Primary Crash Sensor Feed/Return Circuit Open
84 Intermittent or Repaired RH Radiator Primary Crash Sensor Not Mounted to Vehicle
85 Intermittent or Repaired LH Radiator Primary Crash Sensor Not Mounted to Vehicle
Rapid Continuous Flashing of Air Bag Indicator (No Diagnostic Trouble Code) Both Primary Crash Sensors Disconnected Assembly Plant Mode

TROUBLE CODE CLEARING

1. Follow the diagnostic procedures to service the fault condition flashing on the air bag indicator prior to code clearing.

2. Cycle the ignition switch to OFF and then to RUN.

3. Observe air bag indicator prove-out (six ? two seconds) followed by diagnostic trouble code (52-85) flashing completely one time.

4. Locate the Diagnostic "Trouble Code Clear" Connector (grey connector). located underneath the glove compartment, left side (06010) containing Circuits 631 (T/R) and 57 (BK).

5. Use a jumper wire to short Circuit 631 (T/R) to Circuit 57 (BK) or to another good ground. This short must be made after the diagnostic trouble code flashes completely one time, but before the warning light stays on continuously.

6. Hold short until air bag diagnostic monitor tone sounds (approximately five seconds).

7. Release short on Circuit 631 (T/R) to Circuit 57 (BK). This short must be released within 25 seconds after the diagnostic monitor tone sounds.

Diagnostic trouble code is now cleared from memory. Next highest priority diagnostic trouble code stored (if one exists) will begin flashing.

The codes and clearing proceedure above are to be used as a guide, NO claims are implied as to the correctness or accuracy of either.

with so many disseparate systems failing have you checked the earth connection on your battery to the car frame is it good

There's a TSB out for this concern. Its just a faulty relay

Printable View (8 KB) TSB
98-13-19

• ELECTRICAL - LOSS OF 4X4 SYSTEM
• LAMP - 4X4 LAMP ILLUMINATED
• LAMP - NO INTERIOR LIGHTING
• MOON ROOF - INTERMITTENT OR LOSS OF POWER
• REAR WIPER - INTERMITTENT OR LOSS OF POWER
• WINDOWS - INTERMITTENT OR LOSS OF POWER

Publication Date: JULY 6, 1998
LIGHT TRUCK: 1997-1998 EXPLORER, MOUNTAINEER
This TSB article is being republished in its entirety to correct the Service Procedure Steps. ISSUE: A flashing 4X4 lamp and/or a intermittent or loss of:

• Power windows
• Interior lights
• Rear wiper (if equipped)
• Moon roof (if equipped)
• 4x4 system (if equipped)

may occur on some vehicles. This may be caused by an intermittent Battery Saver, Accessory Delay or One-Touch-Down Relay operation and possible chafing of vehicle wire harness.
ACTION: Repair the affected circuit, and/or replace the Battery Saver, Accessory Delay, or One-Touch-Down Relay. Refer to the following Diagnostic/Service Procedure for details before replacing any components.
DIAGNOSTIC/SERVICE PROCEDURE Accurately RECORD ALL Diagnostic Trouble Codes (DTCs) from the Generic Electronic Module (GEM). The following codes can be generated by a faulty relay:

• B1371-Illuminated Entry Relay-Circuit
• B1302-Accessory Delay Relay-Circuit
• B1398-One-Touch-Down Relay-Circuit 1
• B1814-Rear Wiper Motor Down Relay-Circuit
• B1818-Rear Wiper Motor Up Relay-Circuit
• P1820-Transfer Case L2H Relay-Circuit
• P1824-Clutch Relay-Circuit
• P1828-Transfer Case H2L Relay-Circuit

DIAGNOSIS

1. If you have any of these codes B1371, B1814, B1818, and/or the interior lights or rear wipers are part of the customer concerns, go to Step 12. Otherwise locate the Accesory Delay Relay and proceed to next Step.
2. Put key in "RUN."
   1. If conditions are repeatable, go to Step 3.
   2. If conditions are not repeatable, follow standard GEM troubleshooting procedures.
3. Operate the windows until they fail then proceed to next Step.
4. Remove relay from relay box then proceed to next Step.
5. Check for battery voltage at Pin 87.
   1. If battery voltage is present, go to Step 6.
   2. If battery voltage is not present, go to Step 23.
6. Check for battery voltage at Pin 86.
   1. If battery voltage is present, go to Step 8.
   2. If battery voltage is not present, go to Step 7.
7. Locate the Battery Saver Relay and check Pin 3 for battery voltage.
   1. If battery voltage is present, go to Step 23.
   2. If battery voltage is not present, go to Step 16.
8. Return the Accessory Delay Relay back to the relay box then proceed to next Step.
9. Check for Ground at Pin 85.
   1. If Ground is present, go to Step 10.
   2. If Ground is not present, follow standard GEM troubleshooting procedures.
10. Check for battery voltage at Pin 30.
    1. If battery voltage is present, follow normal GEM diagnostic procedures.
    2. If battery voltage is not present, go to Step 11.
11. Check all female terminals at the relay.
    1. If all terminals are tight and all wiring crimps are good, REPLACE the Accessory Delay Relay, then go to Step 22.
    2. Make sure all terminals are tight and all wiring crimps are secure then go to Step 9.
12. Locate the Battery Saver Relay.
13. Put key in "RUN."
    1. If conditions are repeatable, go to Step 14.
    2. If conditions are not repeatable, follow standard GEM troubleshooting procedures.
14. Operate the windows until they fail then proceed to next Step.
15. Remove relay from relay box then proceed to next Step.
16. Check for battery voltage at Pin 1.
    1. If battery voltage is present, go to Step 17.
    2. If battery voltage is not present, go to Step 23.
17. Check for battery voltage at Pin 5.
    1. If battery voltage is present, go to Step 18.
    2. If battery voltage is not present, go to Step 23.
18. Return the Battery Saver Relay back to the relay box then proceed to next Step.
19. Check for Ground at Pin 2.
    1. If Ground is present, go to Step 20.
    2. If Ground is not present, follow standard GEM troubleshooting procedures.
20. Check for battery voltage at Pin 3.
    1. If battery voltage is present, follow standard GEM troubleshooting procedures.
    2. If battery voltage is not present, go to Step 21.
21. Check all female terminals at the relay.
    1. If all terminals are tight and all wiring crimps are good, REPLACE the Battery Saver Relay, then go to Step 22.
    2. Make sure all terminals are tight and all wiring crimps are secure then go to Step 19.
22. Verify all concerns are corrected.
    1. If all concerns are corrected, return vehicle to customer.
    2. If all concerns are NOT corrected, go to Step 23.
23. This is Not a GEM-related issue. Follow standard troubleshooting procedures.

PART NUMBER PART NAME F5TZ-14N089-B Relay - One-Touch-Down And Battery Saver FOAZ-14N089-A Relay - Accessory Delay F77Z-14B205-AA Generic Electronic Module (GEM) (1997 4X2) F77Z-14B205-BC Generic Electronic Module (GEM) (1997 4X4) F87Z-14B205-BA Generic Electronic Module (GEM) (1998 4X2) F87Z-14B205-CB Generic Electronic Module (GEM) (1998 4X4)
OTHER APPLICABLE ARTICLES: NONE
SUPERSEDES: 98-11-6
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME 981319A Perform Pinpoint Tests 1.0 Hr. 981319B Replace Relay 0.2 Hr.
DEALER CODING BASIC PART NO. CONDITION CODE 14B205, 14N089 42
OASIS CODES: 102000, 105000, 201100, 202000, 203200, 206000, 502000, 504000, 508000

Copyright © 1998 Ford Motor Company

Take the liftgate inside panel off an check the wiring , connections etc....
rear door hatch lock repair GMC Chevrolet
chevy tahoe lift gate not opening
The liftgate will lock any time the vehicle is shifted out of park on vehicles equipped with an automatic transmission and at vehicle speeds exceeding 5 kph with manual transmission. This happens in conjunction with auto door locks if enabled or independently of auto door locks if the feature is disabled. This ensures that the liftgate is locked anytime the vehicle is shifted out of park or when the vehicle is in motion.
The liftgate lock relay supply and coil sides receive a constant voltage through the battery voltage supply circuit and the ECC fuse. The normally closed contact is connected to ground and the control side is connected to the body control module (BCM). A lock function will occur when a door lock switch activation, keyless entry lock transmission, auto door lock function or a liftgate lock function has been received by the BCM. The BCM will then ground the control side of the liftgate lock relay. This energizes the relay and allows voltage to be applied to the liftgate lock actuator lock control circuit. Since the other side of the liftgate lock actuator is connected to the normally closed contacts of the door unlock relay to ground, the liftgate will lock. When an unlock function occurs the BCM will ground the control side of the unlock relay and the rear doors and liftgate will unlock.
The BCM also runs diagnostics on the liftgate lock relay control circuit and will set DTC B3825 as current and also send a Class 2 message to the DIC. The DIC will display REPLACE LIFTGATE FUSE to inform the driver that a fault has been detected in the liftgate lock circuit and that the liftgate is not locked. Faults that will set the DTC and cause the DIC to display the message could be any of the following

Power Door Locks Inoperative - Endgate/Liftgate

Schematic Reference: Door Lock/Indicator Schematics
Connector End View Reference: Power Door Systems Connector End Views
1
Did you perform the Diagnostic System Check - Vehicle?
YES - Go to Step 2
NO - Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
Activate the door lock switches to the lock and unlock positions.
Do both rear passenger doors lock and unlock?
YES - Go to Step 3
NO - Go to Power Door Locks Inoperative
3
Did the liftgate lock actuator lock and unlock?
YES - Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
NO - Go to Step 4
4
Disconnect liftgate door lock actuator.
With a test lamp connected to a good ground, probe the door lock actuator lock circuit at the door lock actuator harness connector.
Activate a door lock switch to lock position.
Does the test lamp illuminate?
YES - Go to Step 5
NO - Go to Step 7
5
With a test lamp connected to a good ground, probe the door lock actuator unlock circuit at the door lock actuator harness connector.
Activate a door lock switch to unlock position.
Does the test lamp illuminate?
YES - Go to Step 6
NO - Go to Step 8
6
Inspect for poor connections at the harness connector of the door lock actuator. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?
YES - Go to Step 10
NO .. Go to Step 9
7
Repair the open door lock actuator lock circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
YES - Go to Step 10
--
8
Repair the open in the door lock actuator unlock circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 10
--
9
Replace the liftgate door lock actuator. Refer to Door Lock Actuator Replacement in Body Rear End.
Did you complete the repair?
Go to Step 10
--
10
Operate the system in order to verify the repair.
Did you correct the condition?
System OK
Go to Step 2

HI...
The common cause of the problem that you related.
Is the FUEL PUMP RELAY " Called MAIN RELAY.
Is located : left side under the dash.
Is a BIG relay gray colour. with a connector of 7 or 8 wires.
I recomend replace the relay.

And letme know if you solve your problem.

I hope this information work on your problem.
Thank you for use fixya.