GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Body Rear End Schematics

1

Did you perform A Body Rear End Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Body Rear End

2

Ignition ON, close the liftgate and liftglass.

Is the gate/ajar indicator or rear access open displayed?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3

  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. With a scan tool, observe the Liftgate Ajar Switch and the Liftglass Ajar Switch parameters in the liftgate control module (LGM) data list.

Do either of the parameters display ajar?

Go to Step 4

Go to Step 10

4

Disconnect the active switch.

Does the scan tool display inactive?

Go to Step 6

Go to Step 5

5

Test the liftgate or liftglass ajar switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

6

Inspect for poor connections at the harness connector of the liftgate or liftglass ajar 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 8

7

Inspect for poor connections at the harness connector of the liftgate control module (LGM). 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 9

8

Replace the liftgate or liftglass ajar switch.

Did you complete the replacement?

Go to Step 11

--

9

Important: When replacing the liftgate control module (LGM), refer to Rear Body Control Module Programming in Body Control System.

Replace the LGM. Refer to Liftgate Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 11

--

10

Replace the instrument panel cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages, and Console.

Did you complete the repair?

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