Backup Lamps Inoperative. Chevrolet Kodiak C-Series (Conventional) C6/C7/C8 2003

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2003 🢒 Kodiak C-Series (Conventional) C6/C7/C8 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Backup Lamps Inoperative

Backup Lamps Inoperative RPO M74, MX4, and MTW

Test Description

The numbers below refer to the step numbers on the diagnostic table.

Listen for an audible click when the reverse relay operates. Repeat as necessary.

Tests for voltage at the control side of the reverse relay.

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 in Wiring Systems
1	Did you review the backup lamps operation and perform the necessary inspections?	Go to Step 2	Go to Symptoms - Lighting Systems
2	Block the wheels and set the parking brake. Turn ON the ignition, with the engine OFF. Place the gear selector in and out of the reverse position. Do the backup lamps operate properly?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Turn ON the ignition, with the engine OFF. Move the gear selector in and out of the reverse gear position. Does the reverse lamp relay turn ON and OFF with the gear selector's position?	Go to Step 6	Go to Step 4
4	Turn OFF the ignition. Disconnect the reverse relay. Refer to Relay Replacement in Wiring Systems. Turn ON the ignition, with the engine OFF. Probe the reverse relay control side supply voltage circuit with a test lamp that is connected to a good ground. Does the test lamp illuminate?	Go to Step 5	Go to Step 14
5	Turn OFF the ignition. Connect a test lamp between the reverse relay control side supply voltage circuit and the reverse lamp relay control circuit. Turn ON the ignition, with the engine OFF. Move the gear selector in and out of reverse gear position. Does the test lamp turn ON and OFF in with the gear selector's 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 a good 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	Turn OFF the ignition. Remove the inoperative backup lamp bulb. Connect a test lamp between the backup lamp supply voltage circuit and the backup lamp ground circuit. Turn ON the ignition, with the engine OFF. 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 voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. 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 in Wiring Systems. 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 in Wiring Systems. 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 in Wiring Systems. 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 in Wiring Systems. 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 in Wiring Systems. 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 in Wiring Systems. 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 in Wiring Systems. Did you complete the repair?	Go to Step 20	--
17	Replace the reverse relay. Refer to Relay Replacement in Wiring Systems. 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 Transmission Control Module Replacement in Automatic Transmission - Allison. 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 in Wiring Systems
1	Did you review the backup lamps operation and perform the necessary inspections?	Go to Step 2	Go to Symptoms - Lighting Systems
2	Block the wheels and set the parking brake. Turn ON the ignition, with the engine OFF. Place the gear selector in and out of the reverse position. Do the backup lamps operate properly?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Turn OFF the ignition. Disconnect the backup lamp switch or the neutral start backup switch. Turn ON the ignition, with the engine OFF. Probe the ignition positive voltage circuit of the appropriate switch connector with a test lamp that is connected to a good ground. 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	Turn OFF the ignition. Remove the inoperative backup lamp bulb. Connect a test lamp between the backup lamp supply voltage circuit and the backup lamp ground circuit. Turn ON the ignition, with the engine OFF. 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 in Wiring Systems. 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 in Wiring Systems. 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 in Wiring Systems. Did you find and correct the condition?	Go to Step 13	Go to Step 11
9	Repair an open, high resistance, or short to ground in the ignition positive voltage circuit of the appropriate switch. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. 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 in Wiring Systems. Did you complete the repair?	Go to Step 13	--
11	Replace the appropriate backup lamp switch. Refer to Park/Neutral Backup Switch Replacement in Automatic Transmission - Allison or Backup Lamp Switch Replacement in Manual Transmission - Medium Duty and Backup Lamp Switch Replacement in Manual Transmission - ZF S - 650. 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