I have a 97 F-150 and my airbag is flashing a code 12. I checked the fuse under the hood and found it was blown. I tried to replace it but it keeps blowing the fuse. Does anyone know what would cause this other than the obvious shorted wire. I heard there is something in the airbag control module that causes the fuse to blow if there is a problem. Has anyone had this problem. This started just before I had to replace the battery in the truck.

 

Normal Operation

The air bag diagnostic monitor (14B056) measures the voltage at pin C209-14, circuit 937 (R/W), of the air bag diagnostic monitor connector. Voltage at pin C209-14, circuit 937 (R/W) should be equal to battery voltage. If the voltage at pin C209-14, circuit 937 (R/W), drops to less than 8 volts, the air bag diagnostic monitor will flash a lamp fault code (LFC) 12 on the air bag indicator. If the voltage at pin C209-14, circuit 937 (R/W), drops to less than 5 volts, the diagnostic trouble code (DTC) B1867 will also be stored in memory. Should the loss of battery voltage at pin C209-14, circuit 937 (R/W), be intermittent or repaired, the air bag diagnostic monitor will flash a LFC 52 (or higher priority code if one exists) on the next ignition switch cycle.


Possible Causes

WARNING: DO NOT UNDER ANY CIRCUMSTANCES SUBSTITUTE ANOTHER FUSE VALUE FOR THE 10A BATTERY FUSE 2. ANY FUSE OTHER THAN 10A MAY CAUSE DISARMING FAILURE AND MAY RESULT IN DANGER TO THE OCCUPANTS OF THE VEHICLE. DO NOT ATTEMPT TO REPLACE THE 10A FUSE 2 UNLESS THE AIR BAG SYSTEM FIRST HAS BEEN DEACTIVATED. (REFER TO THE DEACTIVATION PROCEDURE IN THIS SECTION).

NOTE: If a short to ground exists on any of circuits 607 (LB/O), 614 (GY/O), 615 (GY/W), or 616 (PK/BK), 1112 (W/LB), 1113 (Y/LG), leading to a LFC 13 or 53 and DTC B1913 or similarly a short to ground exists on any of circuits 617 (PK/O), 619 (PK/W), 624 (Y/W) or 625 (Y/LG) leading to a LFC 14 or 54 and DTC B1914 the air bag diagnostic monitor will activate an internal solid state switch at pin C209-13 of the air bag diagnostic monitor. This causes the battery fuse 2 (10A) to blow, thus disarming the air bag system and preventing inadvertent air bag deployment. If the power distribution box battery fuse 2 has blown, it must be replaced by a 10A fuse.

Low voltage at air bag diagnostic monitor pin C209-14, circuit 937 (R/W), can be caused by:

An open in the battery circuit that would prevent battery positive voltage (B+) from reaching the air bag diagnostic monitor pin C209-14, circuit 937 (R/W).
A short to ground on the battery feed circuit between the fuse 2 (10A) and pin C209-13, circuit 937 (R/W), or pin C209-14, circuit 937 (R/W), of the air bag diagnostic monitor.
A concern in the charging system causing battery voltage to drop below 8 volts.
After the air bag diagnostic monitor has disarmed the air bag system, it will not be enabled until the appropriate condition (DTC B1913 or B1914) has been repaired and cleared by performing the appropriate pinpoint tests.

 

Hey Homer, Do you have the airbag schematic for a 97? I checked for shorts on what you posted, but didnt find anything wrong. I couldnt find a couple of the wire colors in your post like the pk/bk wire. Also the air bag module is what is causeing the fuse to blow. I can get good power to the connector until I plug it in, then it blows the fuse. Is there a way to get the internal switch to open?

 

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I dont think there is anything you can fix in the airbag module and Ford tells us not to try. You never know though.

 

Are you unplugging it at the base of the columb or removing the bag and unplugging it at the wheel? If you are unplugging it at the base of the columb you may just have a bad clock spring behind the steering wheel.. which is far more common.

 

I was checking for shorts at the air bag diag module connector according to your original post. Your schematic helps alot, but I still dont see a problem. I guess I'll have to break down and take it to the dealer. Thanks for the help tho!