Power Door Locks - Unlock Inoperative Lock Operates

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Step	Action	Yes	No
Schematic Reference: Door Lock/Indicator Schematics DEFINITION: This diagnostic table should be used to diagnose a complete failure of all the unlock functions.
1	Did you perform the Door Systems Diagnostic System Check?	Go to Step 2	Go to Diagnostic System Check - Door Systems
2	Actuate each door lock switch, one at a time, to the unlock position. Did the doors unlock from each switch?	Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONS	Go to Step 3
3	Did the doors unlock from any switch?	Go to Power Door Locks Inoperative - One Door or Switch	Go to Step 4
4	Install a scan tool. With a scan tool, command the doors to unlock. Did the doors unlock?	Go to Step 5	Go to Step 6
5	With a scan tool, observe the passenger door unlock parameter. Actuate a door lock switch to the unlock position. Does the passenger door unlock parameter change state?	Go to Step 20	Go to Step 13
6	Remove the door unlock relay. Connect a test lamp between the battery positive voltage circuit on the coil side of the door unlock relay at the fuse block and a good ground. Does the test lamp illuminate?	Go to Step 7	Go to Step 18
7	Connect a test lamp between the battery positive voltage circuit on the switched side of the door unlock relay at the fuse block and a good ground. Does the test lamp illuminate?	Go to Step 8	Go to Step 18
8	Connect a test lamp between the door unlock control circuit of the door unlock relay at the fuse block and a good ground. With a scan tool, command the doors to unlock. Did the test lamp illuminate?	Go to Step 9	Go to Step 14
9	Remove the door lock relay. Connect a test lamp between the ground circuit on the switched side of the door lock relay at the fuse block and B+. Does the test lamp illuminate?	Go to Step 10	Go to Step 19
10	Install the door unlock relay. Connect a fused jumper between the switched side ground circuit and the load side of the door lock relay at the fuse block. With a scan tool, command the doors to unlock. Did the doors unlock?	Go to Step 12	Go to Step 11
11	Inspect for poor connections at the door unlock relay. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS . Did you find and correct the condition?	Go to Step 21	Go to Step 16
12	Inspect for poor connections at the door lock relay. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS . Did you find and correct the condition?	Go to Step 21	Go to Step 17
13	Test for an open in the door unlock control circuit between the BCM and the door lock switches. Refer to CIRCUIT TESTING and WIRING REPAIRS . Did you find and correct the condition?	Go to Step 21	Go to Step 15
14	Test for an open in the door lock control circuit between the BCM and the door unlock relay. Refer to CIRCUIT TESTING and WIRING REPAIRS . Did you find and correct the condition?	Go to Step 21	Go to Step 15
15	Inspect for poor connections at the BCM. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS . Did you find and correct the condition?	Go to Step 21	Go to Step 20
16	Replace the door lock relay. Did you complete the repair?	Go to Step 21	-
17	Replace the door unlock relay. Did you complete the repair?	Go to Step 21	-
18	Repair the open in the door lock relay battery positive voltage circuit. Refer to CIRCUIT TESTING and WIRING REPAIRS . Did you complete the repair?	Go to Step 21	-
19	Repair the open in the door lock relay ground circuit. Refer to CIRCUIT TESTING and WIRING REPAIRS . Did you complete the repair?	Go to Step 21	-
20	Replace the BCM. Refer to BODY CONTROL MODULE REPLACEMENT . Did you complete the repair?	Go to Step 21	-
21	Operate the system in order to verify the repair. Did you correct the condition?	System OK	Go to Step 2