Test Notes

Normal Operation
The air bag indicator lamp is designed to illuminate for approximately six seconds when the ignition key is turned to the ON position. This initial six seconds of air bag indicator illumination (continuous lamp) is considered normal operation and is called "prove-out" of the air bag indicator. If the diagnostic monitor detects any faults in the air bag system following prove out, it will flash the air bag indicator a series of times to indicate the diagnostic trouble code that has been detected. If the air bag indicator comes on when the ignition key is turned to the ON position and stays on for more than eight seconds continuously, then a fault exists in the air bag indicator circuit.

The air bag diagnostic monitor uses a solid state circuit that shorts the air bag indicator line (Circuit BK/Y) to ground to turn the air bag indicator on. When the gray diagnostic monitor harness connector is unplugged from the diagnostic monitor, a shorting bar within the harness connector connects Pins 4 (air bag indicator) and 5 (ground) together. Therefore, the shorting bar will turn the air bag indicator on whenever the gray diagnostic monitor harness connector is disconnected. Because the shorting bar makes a continuous connection between Pins 4 and 5 when the connector is disconnected, the air bag indicator will not flash-instead, it will glow continuously.

When the ignition key is turned ON, the diagnostic monitor "wakes up" and after approximately six seconds turns the air bag indicator OFF. If the diagnostic monitor fails to "wake up", the lamp driver circuit will automatically turn the air bag indicator ON continuously indicating a concern in the air bag diagnostic monitor or at the gray diagnostic monitor connector.

Possible Causes
Continuous glowing of the air bag indicator can be caused by:
1. A disconnected or poorly connected diagnostic monitor may not push the shorting bar between Pins 4 and 5 into its fully retracted position. This pulls the air bag indicator circuit to ground and causes the air bag indicator to glow continuously.
2. Shorted air bag lamp wiring between Circuit (BK/Y) and ground.
3. A damaged or worn diagnostic monitor.