Ian A

This is a shot in the dark I guess, but does anybody know where abouts the wiring comes through to the dashboard from the driver seat in order to illuminate the seatbelt warning light?

Mine is not lighting, and having checked the plug under the seat (connected ok) it would seem to be a problem at the other end.

On my '90 C4 the wiring *from* the seat is brown/brown&red, but i cant find a trace at the dashboard end

I have had the clock out and re-soldered all the joints also - to no avail.

Thanks in advance for any help!

Ian A

J-McDonald

The clock isn't a very expensive part (around $150 new, much less from a breaker); you might want to try just replacing it.

Remember that any time the clock is removed and power is supplied, it will trigger the warning light, which can only be extinguished using the Bosch Hammer.

johnfm

Ian

all you have checked at the seat end is the connection, yes? Haave you checked to see whether plugging/unplugging the seat belt makes/breaks a circuit?? This should be simple enough with a multimeter. I would check to see whether this works before messing behind the dash.

Ian A

If power is supplied with the clock out, which warning lights are permanently triggered (purely out of interest)?

I will try the multimeter test - I assume it is a simple enough circuit, completed whenever the belt buckle is in place and completing the circuit?

Thanks for your advice all - will let you know how I get on!

Ian A

Dave R.

Ian,

If power is supplied with the clock disconnected, then a fault code will be set by the airbag controller that causes both the airbag warning light and the seatbelt warning light to be lit. The fault code will remain until reset with a Bosch Hammer.

This might be obvious, but have you checked the lightbulb that illuminates the seatbelt warning?

Toddimus

I'll take this opportunity to thank Adrian and Bill W. and everybody else who contributes to this forum. This list is great!! <img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

On to my question, I've got a similar airbag light issue...

My seatbelt light never turns on, and the airbag light is now continually on, with the "!" light until I clear it with the button on the center console. This problem began about 2 weeks ago. Before that, I only got the brake/awd system at the first startup of the day, and after work. (brake/awd lights go out after 10-20 seconds)

To be more specific, when I turn the key, without starting the engine, all the lights seem to light up, except the seatbelt light. After starting the engine, the airbag light temporarily goes out, but comes back on continuously, along with the "!" light (which I then clear). The rest of the lights go out.

<img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" /> I spent the last two hours reading a lot of posts from the last two years' Rennlist posts, and haven't come up with somebody who has my same problem exactly. It would seem that Herbie had the most similar problem, but I didn't didn't get a complete answer from the posts.

Adrian has suggested that the codes should be read and cleared before any troubleshooting is done. This makes sense to me, but I wonder if it would compromise anything if I were to check the bulb (and solder connections of the clock, while I'm at it!)? If I were to do this bulb/solder check, I gather that I should disconnect the battery for 30 mins. beforehand to avoid a fault log (although I already seem to have a fault logged).

I figure, this way, when I go to get beaten with the hammer, I will have done preventative maintenance to keep myself from having to do another fault clear. Am I completely off base?

Adrian, I'd be curious what you think about my problem. I've learned a lot about my 964 from your posts and answers. I got my '90 C4 about 2 months ago, and am trying to figure out all of its systems. It's quite a bit different from the 911sc's that I've had before. Man, I wish that the "hammer" was cheaper, or unnecessary. Or even better, if I could just hook up my laptop to the car and read/clear the codes from the computer.

Whew, that was a lot of typing!

Cheers,
Todd

Dave R.

Todd,

Taking a look before Hammering sounds reasonable to me, especially if you are curious and willing to tinker.

To avoid logging (additional) faults you don't need to disconnect the battery, you just need to be sure you don't power up the electronics with the clock disconnected by turning the key in the ignition.

Toddimus

Dave,

Are you sure that it will log a fault if the battery is disconnected? I would hope the folks in Stuttgart had allowed for a "hammerless" battery change.

I'll check the seatbelt wiring at the seatbelt itself as well. Does anyone know whether the electrical contact is open or closed with the seatbelt undone?

Cheers,
Todd

shaker71

It only sets a fault if the battery is connected while the clock is out. I had a similar problem except my seatbelt light came on and the airbag light did not. When I started checking I found several poor connections at the bulbs. All I had to do was R&R them and they made good contact. I checked my clock and found all the solder connections .002 Ohms.

Good Luck

Bill

Toddimus

Thanks Bill, just as I had thought/hoped. Saturday morning it is. I'll disconnect the battery Fri night, and I'll pull the clock out in the morn. I bet I find the seatbelt light bulb burnt out, and the airbag light will stay on anyways; thus requiring a visit to the hammer. That's ok, I wanted to go see my local 911 doctor for a hammer checkup anyways.

I'll let you know what happens next, if you're still interested.

Cheers,
Todd

Dave R.

Todd,

Please post the fault codes that the Hammer turns up. I'm curious.

Disconnecting the battery before disconnecting the clock module will work fine to avoid setting fault codes. Leaving the ignition switch in the off position instead of disconnecting the battery should also work fine.

Fault codes are set when controllers in the car see things they don't like. If the controller in question (e.g., the airbag controller) is not powered up, then it cannot set a fault code, let alone detect a fault condition. The airbag controller is not powered up when the ignition is off or the battery is disconnected.

When the airbag controller is powered up and alive, it apparently expects to see some signals from the clock module. When it does not (as when the clock module is disconnected or the airbag warning light is burned out), it will set one or more fault codes.

Toddimus

Bill, I might not get to the hammer code check/reset for a week or two, so bear with me. I will, however check the bulb this weekend. I'll tell you what I find.

Thanks for all the info!

-Todd

Toddimus

I said Bill, I meant Dave. Sorry.

I'm not so good at remembering names from the time I read the messages, to the time I go to write them.

-Todd

Toddimus

Well, over the weekend I investigated the problem a bit, and found some interesting things...

First, I took the clock out and found the seatbelt light to be intact, but not lighting up. I also checked the seatbelt contacts and they were functioning correctly as well, so why no seatbelt light? I looked at the electrical schematic a bit more closely and found that the seatbelt light is in series with the "gong". The gong had been removed by the PO, but I still have it, so I put it in and, shazaam! the seatbelt light works properly. In fact, it stays on all the time, along with the airbag light. I guess I've got bigger problems to find in the airbag system.

While I was messing around, I investigated the little green light on the oil temp/press gauge. It's a picture of the AWD system, but it never lights up. I put a bulb in there from the convertible top light (mine's a coupe), and now the green light lights up along with the little yellow one next to the AWD lock **** on the center dash. A nice little thing. I had heard that this might work, but I hadn't tried it yet.

I'll update when I get hammered to read/clear the codes.

Cheers

Ian A

Hmmm - interesting about that gong, Toddimus.

Going to check mine out this weekend - maybe that's why my seatbelt light doesnt illuminate aswell....

Will report back

Ian A