Backup Lamps Inoperative. GMC Truck GMC C-Series Medium Duty Truck B7 2001

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC C-Series Medium Duty Truck B7 🢒 Body and Accessories 🢒 Lighting Systems 🢒 Backup Lamps Inoperative

Step	Action	Yes	No
Schematic Reference: Exterior Lights Schematics
1	Did you review the exterior lighting description and operation and perform the necessary inspections?	Go to Step 2	Go to Symptoms - Lighting Systems
2	Probe the upfitter connector's backup lamp supply voltage circuit with a test lamp that is connected to a good ground. Apply the parking brake. Turn ON the ignition, with the engine OFF. Place the transmission in reverse. Does the test lamp illuminate?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Disconnect the appropriate backup lamp switch. Probe the ignition positive voltage circuit of the backup lamp switch with a test lamp that is connected to a good ground. Does the test lamp illuminate?	Go to Step 4	Go to Step 7
4	Connect a 10 amp fused jumper wire between the ignition positive voltage circuit and the backup lamps supply voltage circuit of the appropriate backup lamp switch connector. Probe backup lamp supply voltage circuit, at the upfitter connector, with a test lamp that is connected to a good ground. Does the test lamp illuminate?	Go to Step 6	Go to Step 5
5	Does the fuse in the jumper wire open?	Go to Step 8	Go to Step 9
6	Inspect for poor connections at the harness connector of the appropriate backup lamp 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 11	Go to Step 10
7	Repair an open, high resistance, or short to ground in the backup lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 11	--
8	Repair a short to ground in the upfitter connector's backup lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 11	--
9	Repair an open or high resistance in the upfitter connector's backup lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 11	--
10	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. Did you complete the replacement?	Go to Step 11	--
11	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 3