Warning Buzzer (not coolant)
 

Hey everyone, I've been out of the FD business since the early 2000's. However, I recently had a '93 drop into my lap that needs a little TLC, but is overall in pretty good shape.

The first issue I need to correct is that, on key on, a buzzer starts going off. I believe it is the buzzer that is mounted somewhere near the driver's left foot at the firewall (left hand drive car). I haven't had time to track it down exactly, but I don't think it is the buzzer in the instrument panel. Also, my add coolant light works, but is NOT ON and the coolant is full and burped. The redline buzzer also works, but is a different buzzer than the one causing the problem (different sound).

I've searched, but I just keep coming up with posts about the add coolant buzzer.

I thought it might be airbag related, as when I turn the key on, the airbag light comes on for a second or two and then fades out. I can't remember if that is normal or not, but while the airbag light is fading out, the buzzer kind of warbles a little and then goes back to normal and keeps buzzing.

If you drive the car for a while, the buzzer will eventually turn off, but it takes about half an hour.

There are no warning lights showing while the buzzer continues to sound and the car runs well.

Does anyone have any pointers on what this might be or how to track it down? I'm going to find my old '93 shop manual and wiring diagram to start looking for the cause, but I thought someone here might know something about it.

Thanks

Still thinking its your coolant buzzer
Maybe air in the system or a bad temp sensor? Can't think of what else would buzz. Airbag light is normal on startup

Man I love the redline warning sound!

Dave, I went out to my car to take a picture for you. Check the wire that i have holding in my hand, I know if that wire is unplugged it will trigger the buzzer. Its behind the power steering pump where the main harness connects to the engine harness. Maybe thats it?

Thanks for the input so far. Cymfc3s, I'll check that wire when I get home this evening (didn't see these replies until just now).

The buzzing/tone is definitely coming from the Airbag Diagnostic Module. I pulled the module out and it looks fine. None of the capacitors are leaking or swelled and the resistor/fuse mentioned in the diagnostic module rebuild thread looks fine, though I may replace it anyway.

The factory shop manual says that the tone will sound if the airbag bulb is burnt out. However, the bulb is fine and lights for a few seconds on the first key on. If I key off/key on a few times it only lights the first time.

The FSM says that on each key on, the airbag light should stay on for 4 to 6 seconds and then go off. Can any of you check and see if this happens with repeated key off/key ons? Mine only does it the first time and the light stays off for any subsequent key off/key on until I leave it alone for a while.

I'm thinking it is the diagnostic module, but I'm going to check the continuity between the diagnostic module connectors and the instrument cluster before I do anything else.

I don't suppose anyone has a spare airbag diag module laying around I could test?