Important: A short to ground will cause an open fuse(s). Before performing this diagnostic procedure, inspect the fuse(s) for an open.

1. Disconnect the backup lamps switch connector (manual) or the park/neutral position switch connector (automatic).
2. Turn the ignition switch to the ON position.
3. Connect a test lamp between terminal B of the back-up lamps switch or park/neutral position switch harness connector and ground.

Does the test lamp light?

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Go to Step 2

Go to Step 3

Connect the test lamp between terminal A and terminal B of the back-up lamps switch harness connector or between connector C2 terminal B and terminal F of the park/neutral position switch.

Does the test lamp light?

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Go to Step 4

Go to Step 5

Repair the open in CKT 539 between the fuse block and the back-up lamps switch or the park/neutral position switch.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Backup Lamp System Check

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1. Verify the adjustment of the back-up lamps switch or the park/neutral position switch.
2. If the switch adjustment is unacceptable, replace the switch.

Is the repair complete?

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Go to Backup Lamp System Check

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Test CKT 24 for an open.

Was an open found?

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Go to Step 6

Go to Step 7

Repair the open in CKT 24 between the back-up lamps switch and splice S400. Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Backup Lamp System Check

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Test CKT150 for an open.

Was an open found?

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Go to Step 8

Go to Step 9

Repair open in CKT 150

Is repair complete?

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Go to Backup Lamp System Check

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Repair open or loose connection in either of the following components.

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Go to Backup Lamp System Check

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