khorvath

Hello all,

I was wondering if anyone can help me out.
I have a 1989 S4 and recently I have had an issue. On start-up (sometimes), the brake warning light won't go out. When this stays on the following does not work: 1) Wipers 2)Headlights (wont go up AND no light). 3) Windows and sunroof.

If I turn the car OFF ON AND ON again it will sort of reset and all works again.

Till the next time I turn it off.....Then this all starts over.

ANY ADVICE? Please?

Thanks
KEN

Bilal928S4

Ignition switch may be worn and needs replacement.

dr bob

I would replace the X-bus relay first. It is the one element common to all of those things. The X relay is closed by the ignition (15) circuit, but disabled when the starter is engaged so starter can get full current. It's in position IV on the central electrics panel under the passenger's feet. Lift the battery ground before replacing. The relay is a standard 53B relay, should have one or four in your ride-along spares kit. WYAIT, replace the LH, EZK and fuel pump relays. And based on a parallel thread, the starter relay is a similar candidate. Relays are relatively cheap, and easy to replace in the comfort and safety of your own garage. As opposed to along the side of some lonely highway, blazing sun, rev limiter noise in your ears.

The horn relay is a suitable swap for testing purposes.

G8RB8

I'm not sure about the other symptoms but doesn't the parking brake illuminate the same light? My switch was not hitting the lever all the time and I had an intermittent warning until I fixed it.

khorvath

Thanks all,
I will start with the relay swap and proceed to the ignition switch if that doesn't work.

Ken

dr bob

My parking brake has a separate dash warning light.

The X-bus relay generally supplies power to accessories that might otherwise hog starting current. Headlights, fog lights, HVAC blower and more are shut down when the starter cranks, all fed through that X-bus relay. The primary power to the relay coil is fed by the 15 circuit through the ignition switch. That's the same switch connection that supplies the ignition and fuel injection triggers, so if those are working you can generally rule out the ignition switch as a possble cause. The other side of the relay coil connects to the starter connection to the solenoid, which is low enough impedance to functionally be a ground connection except when the starter is energized by the starter relay in autobox cars or directly by the 50 circuit from the ignition switch in manual cars. So while cranking, there's the same 12V potential on both sides of the X-bus relay coil, and the relay opens.

khorvath

Thanks all

I changed the relays...(all of the 53 ones). For a bit it all seemed better. No stop brake light...and the wipers and headlights worked. Then this morning, the headlight issue returned. The would pop up...but sometimes the light was on, sometimes not. The interior cabin light stayed on too even though the doors were closed properly.
The car was wet from dew in the am. Is there maybe a grounding issue somewhere? Where can i check? Water issue maybe? I do seem to have issues post car wash for a while. Is water getting where it should'nt? Any advice?

KEN

Landshark87

play with the steering wheel/pod height adjustment lately? on my first 928, lowering the steering wheel caused turn signals and other electrical stuff to not work. possibly connections with the flexible circuit board. i raised it up a little, everything worked.

just a thought.

khorvath

I have not messed with that lately...but i do have it on the lowest setting. I will play around with that this evening.
Ken

khorvath

OK. I tried the instrument pod adjustment...made no diff.

I had the car running in the drive and headlights worked fine. 10 minutes later i tried it again and the pods did not even go up...and no headlights. When I drove it yesterday, the light pods came up...but the lights came on and off sporadically.

Any ideas anyone?
Ken

Alan

Wiggle the ignition switch and see if it seems related to your symptoms - I supect it is - you will need a new (OEM) one - avoid the eBay specials.

Installation is not so bad - its just the electrical part of the lock - plugs into the harness and screws to the back of the ignition lock .

Alan

khorvath

OK. Looks like the lights where related to the light switch. Cleaned it and reinstalled....seems ok.

BUT, the I still have issues when i start the car up. The RED STOP LIGHT stays on and the windows, wipers and sunroof don't work. Turn the car off and on again...it is fine.

Any ideas???

Thanks

KEN