Backup Lamps Inoperative RPO M74, MX4, and MTW
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Listen for an audible click when the reverse relay operates. Repeat as necessary.
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Tests for voltage at the control side of the reverse relay.
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Verifies that the control module is providing ground to the reverse relay.
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 - Vehicle? | Go to Step 2 | |
2 |
Do the backup lamps operate properly? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
Does the reverse lamp relay turn ON and OFF with the gear selector position? | Go to Step 6 | Go to Step 4 | |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 14 | |
Does the test lamp turn ON and OFF in with the gear selector position? | Go to Step 12 | Go to Step 9 | |
6 | Probe the reverse relay switch side supply voltage circuit with a test lamp that is connected to ground. Does the test lamp illuminate? | Go to Step 7 | Go to Step 15 |
7 | Connect a 15-amp fused jumper between the reverse relay switch side supply voltage circuit and the backup lamp supply voltage circuit. Do both of the backup lamps illuminate? | Go to Step 12 | Go to Step 8 |
8 |
Does the test lamp illuminate? | Go to Step 11 | Go to Step 10 |
9 | Test the reverse lamp relay control circuit for an open or a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 20 | Go to Step 13 |
10 | Test the backup lamp supply voltage circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 20 | Go to Step 16 |
11 | Inspect for poor connections at the backup lamp bulb. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 20 | Go to Step 18 |
12 | Inspect for poor connections at the reverse relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 20 | Go to Step 17 |
13 | Inspect for poor connections at the harness connector of the transmission control module (TCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 20 | Go to Step 19 |
14 | Repair the open circuit in the reverse relay control side supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 20 | -- |
15 | Repair the open circuit in the reverse relay switch side supply voltage circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 20 | -- |
16 | Repair the open circuit in the backup lamp ground circuit. Refer to Circuit Testing and Wiring Repairs . Did you complete the repair? | Go to Step 20 | -- |
17 | Replace the reverse relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 20 | -- |
18 | Replace the backup lamp bulb. Did you complete the replacement? | Go to Step 20 | -- |
19 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 20 | -- |
20 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |
Backup Lamps Inoperative RPO MWF, MWW, and MWX
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 - Vehicle? | Go to Step 2 | |||||||
2 |
Do the backup lamps operate properly? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | ||||||
3 |
Does the test lamp illuminate? | Go to Step 4 | Go to Step 9 | ||||||
4 | Connect a 15-amp fused jumper wire between the ignition positive voltage circuit of the backup lamp switch or the neutral start backup switch and the backup lamp supply voltage circuit of the backup lamp switch or the neutral start backup switch. Do both of the backup lamps illuminate? | Go to Step 8 | Go to Step 5 | ||||||
5 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 6 | ||||||
6 | Test the backup lamp supply voltage circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | Go to Step 13 | Go to Step 10 | ||||||
7 | Inspect for poor connections at the backup lamp bulb. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | Go to Step 13 | Go to Step 12 | ||||||
8 | Inspect for poor connections at the harness connector of the appropriate switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | Go to Step 13 | Go to Step 11 | ||||||
9 | Repair the following in the ignition positive voltage circuit of the appropriate switch:
Refer to Circuit Testing and Wiring Repairs. Did you complete the repair? | Go to Step 13 | -- | ||||||
10 | Repair the open circuit in the backup lamp ground circuit. Refer to Circuit Testing and Wiring Repairs. Did you complete the repair? | Go to Step 13 | -- | ||||||
11 | Replace the inoperative backup lamp switch. Refer to Park/Neutral Position and Backup Lamp Switch Replacement or Backup Lamp Switch Replacement. Did you complete the replacement? | Go to Step 13 | -- | ||||||
12 | Replace the backup lamp bulb. Did you complete the replacement? | Go to Step 13 | -- | ||||||
13 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 | ||||||
