Chart C - Air Bag Warning Light Does Not Come On: Description

When ignition switch is first turned on, IGNITION 1 voltage is applied from GAUGES fuse to REDUNDANT INDICATOR IGNITION 1 terminal B2 and to AIR BAG warning light which is connected to SIR INDICATOR, terminal B1. AIR BAG fuse applies system voltage to IGNITION 1 inputs, terminals A9 and A10. DERM responds by flashing AIR BAG warning light 7 times.

When engine is cranked, battery voltage is applied from CRANK fuse to DERM at CRANK input. DERM responds by grounding SIR INDICATOR output until battery voltage is removed from CRANK input. This results in AIR BAG warning light being on during cranking. After cranking, DERM will flash AIR BAG warning light 6 times.

1. Checks whether malfunction is in DERM circuit or instrument cluster power feed circuit.
2. Checks integrity of REDUNDANT INDICATOR IGNITION 1 circuit.
3. Checks for an open in SIR INDICATOR circuit, instrument cluster circuit, and AIR BAG warning light.
4. Checks whether open is caused by a bad bulb.
5. Checks whether malfunction is an open in SIR INDICATOR circuit or open in instrument cluster.
6. Checks whether malfunction is a short from SIR INDICATOR circuit to voltage.
   WARNING: To avoid air bag deployment and injury when trouble shooting system, only use test equipment specified in diagnostic charts. Under no circumstances should battery powered test equipment or test light be used. Carefully follow all instructions.
   Fig 1: Chart C - Air Bag Warning Light Does Not Come On (1 Of 2)

   Courtesy of GENERAL MOTORS CORP.
7. Checks whether power is available to instrument cluster power feed circuit.
8. Checks for a short from instrument cluster power feed circuit to ground.
9. Checks whether short to ground is caused by a short in wiring or DERM.
10. Checks whether malfunction is caused by an open power feed circuit from GAUGES fuse to instrument cluster or an open power feed to GAUGES fuse.

Fig 2: Chart C - Air Bag Warning Light Does Not Come On (2 Of 2)

Courtesy of GENERAL MOTORS CORP.