Pinpoint Test W: The Individual Reversing Lamp Is Inoperative

Reversing Lamps

Pinpoint Tests

Pinpoint Test W: The Individual Reversing Lamp Is Inoperative

Refer to Wiring Diagram Set 93, Reversing Lamps for schematic and connector information. Diagrams By Number

When the reversing lamps relay is energized, voltage is routed to the reversing lamps through circuit CLS10 (GN/BN). The LH and RH reversing lamps are provided ground through circuits GD148 (BK/YE) and GD149 (BK/GY), respectively.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Rear lamp jumper harness



PINPOINT TEST W: THE INDIVIDUAL REVERSING LAMP IS INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Make sure the bulb is OK before carrying out diagnostics.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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W1 CHECK FOR VOLTAGE TO THE REVERSING LAMP


- Ignition OFF.
- Disconnect: Inoperative Reversing Lamp.
- Apply the parking brake.
- Ignition ON.
- Select REVERSE.
- Measure the voltage between the LH rear lamp C498-4, circuit CLS10 (GN/BN), harness side and ground, or between the RH rear lamp C499-4, circuit CLS10 (GN/BN), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to W2.

No
REPAIR circuit CLS10 (GN/BN) for an open. TEST the system for normal operation.

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W2 CHECK THE REVERSING LAMP GROUND CIRCUIT FOR AN OPEN


- Disconnect: Negative Battery Cable.
- Measure the resistance between the LH reversing lamp C498-1, circuit GD148 (BK/YE), harness side and ground, or between the RH reversing lamp C499-1, circuit GD149 (BK/GY), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
REPAIR or INSTALL a new rear lamp jumper harness. TEST the system for normal operation.

No
REPAIR the ground circuit in question for an open. TEST the system for normal operation.

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