GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you perform the Instrument Cluster Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Instrument Cluster

2

  1. Turn the ignition switch to the ON position.
  2. Observe the fasten seat belt indicator on the instrument cluster during the bulb check.

Does the fasten safety belt indicator illuminate during the bulb check then turn off?

Go to Step 3

Go to Step 10

3

  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. Ensure the driver's seat belt is unbuckled.
  4. With a scan tool, observe the DRIVER SIDE BELT STATUS parameter the the SIR data list.

Does the scan tool display BUCKLED?

Go to Step 4

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

4

  1. Turn OFF the ignition.
  2. Ensure that the driver's seat belt is unbuckled.
  3. Disconnect the seat belt switch.
  4. Connect a 3 amp fused jumper wire between the signal circuit and the ground circuit of the seat belt switch.
  5. Turn ON the ignition with the engine OFF.
  6. With the scan tool, observe the DRIVER SIDE BELT STATUS parameter.

Does the scan tool display UNBUCKLED?

Go to Step 8

Go to Step 5

5

Test the ground circuit of the seat belt switch for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 6

6

Test the signal circuit of the seat belt switch for the following conditions:

    • An open
    • A short to voltage
    • A high resistance

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 7

7

Inspect for poor connections at the harness connector of the sensing and diagnostic module (SDM). 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 12

Go to Step 9

8

Inspect for poor connections at the harness connector of the seat belt 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 12

Go to Step 11

9

Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement in SIR.

Did you complete the replacement?

Go to Step 12

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10

Replace the instrument cluster (IPC). Refer to Instrument Cluster Replacement .

Did you complete the repair?

Go to Step 12

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11

Replace the seat belt switch.

Did you complete the replacement?

Go to Step 12

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12

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2