Reversing lights

[Epsom Green]

Hi. I have recently purchased a 1997 993 C4 and have just joined this excellent forum. I am delighted with the car but am trying to diagnose a problem with the reversing lights "" they stay on (with reverse gear selected) when the ignition is off!

Understand that the relevant relay is R31 (fog light) and have tried swapping this with a couple of others without success.

Other symptoms which may be related "" the electric windows and sun roof operate with the doors shut and ignition off which should not be the case according to my handbook (though I can hear the a relay R22 (power window) clicking when I operate either door switch) and also relay R21 (sun roof) is warm to the touch even when the car is left overnight which might explain the fairly rapid battery discharge! Other circuits (radio, headlights, wipers, cig lighter etc) are properly disabled when the ignition is off.

By way of background the car has been maintained by the original supplying OPC and apart from a Nokia car kit and Sony CD player fitted when new has not been modified in any way. The problem appeared about six months ago and as far as I know cannot be connected with any work undertaken on the car.

If anyone can shed any light on the possible causes of this fault I would be really grateful.

Steve

 

[968er]

Is there not a switch at the bottom of the gear lever that turns on the reversing lights? If there is this may be stuck, but it does sound as if you have a few more electrical gremlins.

 

[Guest]

Hi Steve, that's an interesting array of issues you've got there. [:-]

Only the sunroof is on R21 and all it is doing is discharging your battery; I'd pull that relay and leave it to be sorted later. (Thinks: The sunroof relay should only be energised when the centre console switch is being operated.)

Regarding the windows/sunroof operating while the doors are shut, I wonder if this could be down to one of the door switches not operating correctly. You would hope to be able to test this by seeing if the interior light came on when each door is opened/closed. (You would need to set the interior lights to come on when a door is opened.)

Another possibility is that the ignition switch is faulty and has failed in a working mode. However, this doesn't seem to explain all the issues so lets not go there now.

Steve, if you look around the dash, does it look as though things have been apart and put back together again? It should be neat and tidy including the wiring under the dash.

Regards

Bob
without a circuit diagram, 993's can be real bitches...

 

[Epsom Green]

Many thanks for the replies.
William - the reversing lights go out when reverse gear is deselected so I fear you are right that there are some more serious gremlins about [].
Maurice "" Thanks for the welcome. I have owned the car for a couple of weeks and the previous owner told me about the problem. Agree it is difficult to see how this could self generate. I would really like to try and resolve this myself so if you have the circuit diagram for a 1997 C4 that would be an enormous help.
Bob - as you say an interesting array of issues [:-]. The interior light comes on correctly when I open either door and I can hear the relay clicking when I operate the door switches so I think they (the door switches) are ok. The car is completely original and I don't think anything has been touched by an amateur (until now!). Had not considered the ignition switch because other circuits are properly disabled but this might be worth some further investigation.
I will keep probing and report back but if anyone has any more thoughts I would really appreciate your input. The 'warm to the touch' sun roof relay is definitely the circuit and not the relay itself. Am I correct in my understanding that the windows and sunroof should not operate when the doors are closed and the ignition is off?
Steve

 

[Wayne]

Just a thought, but have you checked with the OPC that the original wiring loom has been replaced as per the recall on these cars? If not that might be part of the problem!

 

[Epsom Green]

Fixed it [] . It was a faulty relay after all. I had read somewhere that the fog light relay also controlled the reversing lights. The only fog light relay I could find in the chart inside the fuse panel cover was R31 so I incorrectly concentrated on this. It turns out that there is another relay R01 controlling the rear fog lights labelled term. X on my chart. This was the culprit! Out of curiosity could someone clarify what term. (terminal?) X and term.15E on the fuse/relay chart means?

The window problem still persists (windows operate with ingnition off and doors closed - assume this is not correct?). Maurice - the power window relay is permanently activating the sun roof relay. If I remove the power window relay then the sun roof relay no longer stays warm. I will try replacing the window relay and report back.

Thanks for all the help.

Steve

 

[38F3E1]

On your question regarding window operation - on mine with the ignition key off then

1/ Doors are shut and windows do not operate
2/ Open door and windows now operate
3/ Close door and windows do not operate

So yes at least one example seems to work as described in manual.

Ian.

 

[Epsom Green]

Window problem now fixed as well. It was the power window relay.
If anyone is experiencing fairly rapid battery discharge and windows / sunroof operate with ignition off and doors closed it might be worth checking this out.

Once again thank you everyone for your help.

Steve