but I need to ask what is the IAC? My dad made me (with lots of help from him) rebuild the carburetor & change the oil on my 1965 Mustang but that is the extent of my car repairs. I know more about the mechanics than actually being able to do it, I'll plead that I'm a girl LOL. I'll consult with the mechanic pass on info, they will know what to do. Not too sure about messing with the computer, I replaced it a few years ago as I had an idiot "5.0 specialist" that messed it up and the used replacement is working great.
Scroll up/down when you see that you have a reply and reread post #9 since you may have more than one reply by the time you read it. As I said in #9 if your mechanic said that you had a code 12 and it's an
airbag code then that's the code that he was talking about and
not the OBD1 code 12 for the IAC. There are 2
different code 12s but in different systems. Forget that I even mentioned that idle code in post #6. Your mechanic is trying to fix your airbag fault not your idle.
The 3 links in my post #9 detail the specifics of the low voltage to the airbag diagnostic monitor and the multiple causes:
Some causes for the code 12 low diagnostic monitor/module voltage are an open in the battery circuit that would prevent battery positive voltage from reaching the air bag diagnostic monitor, a short to ground on the battery feed circuit between the 10a fuse and the air bag diagnostic monitor, or a problem in the charging system causing battery voltage to drop below 8 volts.