Possible Causes
WARNING: This page is about a different car, the 2002 Mercury Villager. However, it is still accessible from the selected car via links, so may be relevant.
An AIR BAG warning light that is continuously illuminated may be caused by disconnected diagnostic monitor, damaged battery or ignition circuit, loss of ground circuit to diagnostic monitor or inoperative diagnostic monitor.
- Check driver-side & passenger-side air bag modules
Turn ignition switch to OFF position. If driver-side air bag module or passenger-side air bag module is not deployed, go to next step. If air bag module(s) are deployed, disable air bag system. See DISABLING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Replace appropriate air bag module(s). See REMOVAL & INSTALLATION . Reconnect and activate system. See ACTIVATING SYSTEM under DISABLING & ACTIVATING AIR BAG SYSTEM. Perform system operation check. See SYSTEM OPERATION CHECK under . - Check air bag diagnostic monitor connection
Disable air bag system. Access diagnostic monitor and disconnect connector C2003A. See DIAGNOSTIC MONITOR under REMOVAL & INSTALLATION. Ensure air bag diagnostic monitor connectors are free of corrosion and connected securely. If connectors are clean and securely connected, go to next step. If connectors are not clean and securely connected, clean and reconnect connectors as necessary. Reconnect and activate system. Perform system operation check. - Check air bag fuse (10-amp)
Check AIR BAG fuse F56 (10-amp) located in instrument panel fuse/relay block. See Fig 1. If fuse is okay, go to step 5. If fuse is not okay, go to next step. - Check for short in power supply
Turn ignition switch to OFF position. Remove AIR BAG F56 (10-amp) fuse from instrument panel fuse/relay block. Measure resistance between right terminal of fuse F56 holder and ground. If resistance is more than 10 k/ohms, replace fuse and go to next step. If resistance is less than 10 k/ohms, repair short to ground in Red/Blue wire (circuit No. PS01). See WIRING DIAGRAMS . Reconnect and activate system. Perform system operation check. - Check power supply to air bag diagnostic monitor
Turn ignition switch to ON position. Measure voltage between diagnostic monitor connector C2003A, terminals No. 20 (Black wire, circuit No. PSE2) and No. 18 (Red/Blue wire, circuit No. PS01). See Fig 2. If voltage is more than 10 volts, go to step 7. If voltage is less than 10 volts, go to next step. - Check air bag diagnostic monitor ground
Turn ignition switch to OFF position. Measure resistance between air bag diagnostic connector C2003A, terminal No. 18 (Red/Blue wire) and ground. If resistance is less than 5 ohms, repair open in Red/Blue wire. Reconnect and activate system. Perform system operation check. If resistance is more than 5 ohms, repair open in Black wire. Reconnect and activate system. Perform system operation check. - Check air bag indicator circuit
Turn ignition switch to OFF position. Remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Disconnect 20-pin digital instrument cluster connector C267C or 12-pin analog instrument cluster C266B. Measure resistance between digital instrument cluster connector C267C, terminal No. 10 or analog instrument cluster connector C266B, terminal No. 3 and air bag diagnostic monitor connector C2003A, terminal No. 16 (Orange wire, circuit No. PS15). See Fig 2 & Fig 3 . If resistance is less than 5 ohms, replace air bag diagnostic monitor. Reconnect and activate system. Perform system operation check. If resistance is more than 5 ohms, repair open in Orange wire. Reconnect and activate system. Perform system operation check.