Pinpoint Test C: The Door Locks Operate Only One Way
WARNING: This page is about a different car, the 2010 Lincoln Town Car. However, it is still accessible from the selected car via links, so may be relevant.
Refer to appropriate SYSTEM WIRING DIAGRAMS article, Power Door Locks for schematic and connector information.
Normal Operation
The door lock control switches provide voltage to the driver door module (DDM) through circuits 119 (PK/YE) and 120 (PK/LG) for the lock and unlock requests, respectively. When the lock or unlock switch is pressed, the voltage signal is routed to the DDM.
The DDM contains internal relays that are energized depending on input received. When the DDM receives a lock or unlock request from the door lock control switch, the DDM energizes the appropriate relay(s) to lock or unlock the doors.
- DTC B1396 (Power Door Lock Circuit Short To Battery) - is a continuous and on-demand DTC that sets when the DDM detects a short to voltage on the lock input circuit 119 (PK/YE). This DTC may also set if the lock switch is pressed for longer than 2 minutes.
- DTC B1397 (Power Door Unlock Circuit Short To Battery) - is a continuous and on-demand DTC that sets when the DDM detects a short to voltage on the unlock input circuit 120 (PK/LG). This DTC may also set if the unlock switch is pressed for longer than 2 minutes.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Door lock control switch
- DDM
PINPOINT TEST C: THE DOOR LOCKS OPERATE ONLY ONE WAY
NOTE:
Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
- C1 CHECK THE RECORDED DDM DTCs FROM THE SELF-TEST
- Check the recorded results from the DDM self-test.
- Is DTC B1396 or B1397 present?
- C2 CHECK THE LH DOOR LOCK CONTROL SWITCH
- Disconnect: LH Door Lock Control Switch C505
- Enter the following diagnostic mode on the diagnostic tool: DDM Self-Test
- Is DTC B1396 or B1397 present?
- YES : LEAVE the switch disconnected. Go to C3.
- NO : INSTALL a new LH door lock control switch. REFER to Door Lock Control Switch . TEST the system for normal operation.
- C3 CHECK THE RH DOOR LOCK CONTROL SWITCH
- Disconnect: RH Door Lock Control Switch C605
- Enter the following diagnostic mode on the diagnostic tool: DDM Self-Test
- Is DTC B1396 or B1397 present?
- YES : LEAVE the switch disconnected. Go to C4.
- NO : INSTALL a new RH door lock control switch. REFER to Door Lock Control Switch . TEST the system for normal operation.
- C4 CHECK THE LOCK INPUT CIRCUIT OR THE UNLOCK INPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Key in OFF position.
- Disconnect: DDM C501a
- Key in ON position.
- For DTC B1396, measure the resistance between the DDM C501a-9, circuit 119 (PK/YE), harness side and ground.
- For DTC B1397, measure the resistance between the DDM C501a-10, circuit 120 (PK/LG), harness side and ground.
- Is any voltage present?
- YES : REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
- NO : Go to C8.
- C5 VERIFY THE OPERATION OF BOTH DOOR LOCK CONTROL SWITCHES
- Key in OFF position.
- Press the lock and unlock button of both door lock control switches while observing the door lock operation.
- Do the door locks operate only one way from both switches?
- C6 CHECK CIRCUIT 119 (PK/YE) (LOCK INPUT) OR CIRCUIT 120 (PK/LG) (UNLOCK INPUT) FOR AN OPEN (SINGLE SWITCH INOPERATIVE)
- Disconnect: Suspect Door Lock Control Switch
- Unlock the doors from the working door lock control switch.
- Connect a fused (5A) jumper wire between the LH door lock control switch C505-2, circuit 119 (PK/YE), harness side and the LH door lock control switch C505-4, circuit 1524 (DB), harness side; or between the RH door lock control switch C605-2, circuit 119 (PK/YE), harness side and the RH door lock control switch C605-4, circuit 1524 (DB), harness side.
- Remove the jumper wire.
- Connect a fused (5A) jumper wire between the LH door lock control switch C505-6, circuit 120 (PK/LG), harness side and the LH door lock control switch C505-4, circuit 1524 (DB), harness side; or between the RH door lock control switch C605-6, circuit 120 (PK/LG), harness side and the RH door lock control switch C605-4, circuit 1524 (DB), harness side.
- Do the doors lock and unlock with the jumper wire?
- YES : REMOVE the jumper wire. INSTALL a new door lock control switch. REFER to Door Lock Control Switch . TEST the system for normal operation.
- NO : REMOVE the jumper wire. REPAIR the input circuit in question. TEST the system for normal operation.
- C7 CHECK CIRCUIT 119 (PK/YE) (LOCK INPUT) OR CIRCUIT 120 (PK/LG) (UNLOCK INPUT) FOR AN OPEN (BOTH SWITCHES INOPERATIVE)
- Disconnect: LH Door Lock Control Switch C505
- Disconnect: DDM C501a
- If the doors do not lock, measure the resistance between the DDM C501a-9, circuit 119 (PK/YE), harness side and the LH door lock control switch C505-2, circuit 119 (PK/YE), harness side.
- If the doors do not unlock, measure the resistance between the DDM C501a-10, circuit 120 (PK/LG), harness side and the LH door lock control switch C505-6, circuit 120 (PK/LG), harness side.
- Is the resistance less than 5 ohms?
- YES : Go to C8.
- NO : REPAIR the circuit in question. TEST the system for normal operation.
- C8 CHECK FOR CORRECT DDM OPERATION
- Disconnect all the DDM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the DDM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- YES : INSTALL a new DDM. REFER to MULTIFUNCTION ELECTRONIC MODULES article. TEST the system for normal operation.
- NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.