GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The ignition switch supplies battery voltage to the AIR BAG indicator using the ECU-B fuse. The AIR BAG indicator is connected to the AIR BAG indicator control circuit of the SDM. When the ignition switch is first turned to the ON position, the SDM responds by illuminating the AIR BAG indicator for approximately six seconds while performing diagnostic tests on the SIR system.

Diagnostic Aids

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction.

The following are possible causes of the malfunction:

    • A short to ground in the AIR BAG indicator control circuit
    • An internal SDM malfunction

If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The number below refers to the step number on the diagnostic table.

  1. Tests the AIR BAG indicator control circuit for a short to ground.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

1

Did you perform A Diagnostic System Check - SIR?

Go to Step 2

Go to Diagnostic System Check - SIR

2

  1. Turn OFF the ignition.
  2. Disconnect the SDM connector.
  3. Test the Air Bag Indicator Control 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 4

Go to Step 3

3

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

Did you complete the replacement?

Go to Step 4

--

4

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2