Test Notes

Continuous Air Bag Indicator - Diagnostic Monitor Disconnected Or Inoperative

Normal Operation
The air bag indicator 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 8 seconds continuously, then a fault exists in the air bag indicator circuit.

The air bag diagnostic monitor incorporates a solid state circuit that shorts the air bag indicator Circuit 608 (Y/BK) 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 the lamp will be illuminated continuously.

If the computer within the diagnostic monitor fails to "boot up" with the key ON, the lamp driver circuit will automatically turn the air bag indicator ON continuously indicating a problem in the air bag diagnostic monitor or at the gray diagnostic monitor connector.

Possible Causes
Continuous illumination of the air bag indicator can be caused by the following:
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 shorts the air bag indicator line to ground and causes the air bag indicator to illuminate continuously.
2. Shorted air bag indicator wiring.
3. A faulty diagnostic monitor.