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

Open the liftgate or liftglass.

Is the tail gate alarm indicator illuminated?

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

Go to Step 3

3

  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. With a scan tool, observe the liftglass jamb switch parameter in the body control module (BCM) data list.

Does the scan tool display active?

Go to Step 10

Go to Step 4

4

  1. Disconnect the liftgate ajar jamb switch.
  2. Connect a fused jumper between the liftgate ajar jamb switch signal circuit and a good ground.

Does the scan tool display active?

Go to Step 5

Go to Step 6

5

Connect a fused jumper between the liftgate ajar jamb switch signal circuit and the liftgate ajar jamb switch ground circuit.

Does the scan tool display active?

Go to Step 8

Go to Step 7

6

Test the liftgate ajar jamb switch signal 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 9

7

Repair the open or high resistance in the ground circuit of the liftgate ajar jamb switch circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

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8

Inspect for poor connections at the harness connector of the liftgate ajar jamb 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

Inspect for poor connections at the harness connector of the body control module (BCM). 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

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 13

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11

Replace the liftgate ajar jamb switch.

Did you complete the replacement?

Go to Step 13

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12

Important: When replacing the body control module (BCM), refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 13

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13

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3