Pinpoint Test R: The Reversing Lamps Are Inoperative
Reversing Lamps
Pinpoint Tests
Pinpoint Test R: The Reversing Lamps Are Inoperative
Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number
Normal Operation
When the ignition switch is in the RUN position, voltage is provided to the digital Transmission Range (TR) sensor from the Central Junction Box (CJB) through circuit 1789 (VT/WH). When the transmission is placed in REVERSE (R), the digital TR sensor routes voltage to the reversing lamps through circuit 140 (BK/PK). The reversing lamps share a common ground through circuit 57 (BK).
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Digital TR sensor
PINPOINT TEST R: THE REVERSING LAMPS ARE INOPERATIVE
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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R1 CHECK THE DIGITAL TR SENSOR ADJUSTMENT
- Ignition OFF.
- Check the digital TR sensor adjustment.
- Is the digital TR sensor adjusted correctly?
Yes
GO to R2.
No
ADJUST the digital TR sensor. TEST the system for normal operation.
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R2 CHECK CIRCUIT 1789 (VT/WH) FOR AN OPEN
- Disconnect: Digital TR Sensor C167.
- Ignition ON.
- Measure the voltage between the digital TR sensor C167-9, circuit 1789 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to R3.
No
VERIFY the CJB fuse 4 (10A) is OK. If OK, REPAIR the circuit for an open. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short.
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R3 CHECK THE DIGITAL TR SENSOR
- Ignition OFF.
- Connect a fused jumper wire between the digital TR sensor C167-9, circuit 1789 (VT/WH), harness side and the digital TR sensor C167-11, circuit 140 (BK/PK), harness side.
- Ignition ON.
- Do the reversing lamps illuminate?
Yes
REMOVE the jumper wire. INSTALL a new digital TR sensor. TEST the system for normal operation.
No
LEAVE the jumper wire connected. GO to R4.
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R4 CHECK FOR VOLTAGE TO THE REVERSING LAMPS
- Ignition OFF.
- Disconnect: Inoperative Reversing Lamp.
- Ignition ON.
- Measure the voltage between the LH reversing lamp C487-3, circuit 140 (BK/PK), harness side and ground; or between the RH reversing lamp C488-3, circuit 140 (BK/PK), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
REPAIR circuit 57 (BK) for an open. TEST the system for normal operation.
No
REPAIR circuit 140 (BK/PK) for an open. TEST the system for normal operation.
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