Mercury Villager Nissan Quest 1997-2000

Diagnostic Monitor


The diagnostic monitor is located under the driver's side of the instrument panel on 1994-95 vehicles. On 1996-00 vehicles, it is located behind the center console. The main purpose of the diagnostic monitor is to monitor the operational status of the system through continual checks of the system's circuits. In the event the diagnostic monitor detects a fault, the air bag warning indicator on the instrument panel will fail to illuminate when the ignition switch is turned on, remain lit continuously, or flash.

The diagnostic monitor also contains the back-up power supply. In the event of a impact severing the battery or other electrical sources to the air bag system, the back up power supply contains enough power to deploy the air bag(s). The diagnostic monitor contains several small capacitors that store power. The back-up power supply must be discharged before air bag service can be performed.

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Fig. Diagnostic monitor and sensor locations-1994-95 vehicles

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Fig. Diagnostic monitor location-1996-00 vehicles