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Possible Causes

WARNING: This page is about a different car, the 1995 Ford Pickup, 1995 Ford F-Super Duty, 1995 Ford Cab & Chassis, and 1995 Ford Bronco. However, it is still accessible from the selected car via links, so may be relevant.

Code 12 may be caused by an open or short to ground in circuit No. 937, an internal short to ground within safing sensor, a short to ground in circuit No. 611 or circuit No. 612, or a charging circuit problem.

  1. Verify Condition  - Turn ignition on. Check for fault codes. If Code 12 is flashing, go to step 2). If Code 12 is not flashing, check connectors, wiring, splices, crimps and charging circuit for an intermittent problem. DO NOT  proceed with diagnostic test unless code is flashing. Doing so will result in needless replacement of system components.
  2. Voltage Check  - Deactivate air bag system. Refer to COMPLETE SYSTEM DEACTIVATION  under DISABLING & ACTIVATING AIR BAG SYSTEM. Disconnect diagnostic monitor. Diagnostic monitor is located on left side of steering column under instrument panel. Turn ignition on. Measure voltage between terminals No. 13 (Red/White wire) and No. 3 (Black/White wire) of diagnostic monitor Gray connector. See Figure . If battery voltage is not present, go to step 3). If battery voltage is present, replace diagnostic monitor.
  3. Check Instrument Panel Fuse  - Check fuse No. 5 in instrument panel fuse block. If fuse is blown, go to step 4). If fuse is okay, locate and repair open circuit between fuse and terminal No. 13 and then go to step 6).
  4. Check For Short To Ground  - Replace fuse. If fuse does not blow again, go to step 5). If fuse blows again, locate and repair short to ground between fuse and terminal No. 13 of diagnostic monitor. After repair is completed, go to step 6).
  5. Check For Short To Ground In Circuits No. 611 & 612  - Turn ignition off. Reconnect diagnostic monitor. Turn ignition on. Recheck fuse No. 5. If fuse is blown, locate and repair short to ground in circuit No. 611 (White/Orange wire) or circuit No. 612 (Purple/Orange wire). If fuse is okay, short to ground is intermittent. Check all circuits between fuse and terminal No. 13 of diagnostic monitor. Also check circuits No. 611 and 612 for intermittent shorts. Repair as necessary and go to step 6).
  6. Verify System  - Replace fuse as necessary. Reconnect all air bag system connectors. When repairs are complete, check AIR BAG warning light for codes with Air Bag Simulator (105-00010) still in place of air bag module. If system checks okay, reactivate air bag system.
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