Horn and headlights problem

[ducerman]

Hello.

My wife has a 2002 PT Cruiser T.E.

Yesterday a strange thing happened after she started it - when she put the headlights on the horn turned on and wouldn't stop, and the headlights won't turn on. The parking lights work, but the headlight and fog light switches just turn the horn on. I'm suspecting the multi-function switch, but I don't know how the horn fits into the picture. I pulled the horn relay, and the horn fuse, but the headlights still don't work. I also disconnected the battery and re-connected it, hoping to reset the computer - that didn't work. The car has had a remote starter since it was new, and it still works fine - the problem is still there with the remote turned off.
I'll be bringing it to the dealer on Monday.

Anyone have any ideas?

Thanks.

[Hooligan]

ducerman, Welcome to the Forum. As to your problem, I would expect the MF switch, they have been a problem in the past.

[CREWZIN]

I would suspect the multi-function stalk also but I can't find and don't seem to remember anyone ever having a horn problem associated with a light problem. I looked thru the wiring diagram and don't see how they are related. The only thing I can think of is when the multi-function switch goes bad,it actually melts parts together inside the stalk because of the heat generated when the lights are on (shown to some of us by an expert mechanic (MX-5) on another forum). Usually, the head lights/fog lights stay on all the time because of the melting. The horn wires go down the steering column along with the wires related to the multi-function switch, maybe even in the same wiring harness. Maybe somehow the malfunction of the switch is somehow causing a short in the harness that makes the horn blow. Only guessing. The dealer will have to figure that one out, but they'll probably just replace the stalk and everything will be back to normal.

[Cartman]

Are both headlights affected or just one side? If just the right sides headlamp and foglamps are affected id suspect a grounding issue as the horns and right lamps use a common ground. if both headlamps and foglamps are affected Then id have to agree with everyone else and say Multi-function switch.

[quicksilverdon]

Originally Posted by Cartman

Are both headlights affected or just one side? If just the right sides headlamp and foglamps are affected id suspect a grounding issue as the horns and right lamps use a common ground. if both headlamps and foglamps are affected Then id have to agree with everyone else and say Multi-function switch.

Yeah, but how could a ground problem turn the horn on?

[Cartman]

when the proper ground isnt available, power will find a path to ground ANYWHERE. the horns may provide an improptu ground for the headlight system. and seeing as the two systems share a common ground wire, it sounds like a reasonable explanation.

[ducerman]

Hello again.

Thanks for your replies.

I brought the car to the dealer on Monday. The first thing they did was replace the MFS, but it had no effect on the problem. They told me that it was being caused by the remote starter system. I was skeptical, but my wife needed the car and I had to get it working again, so I told them to remove it and see if that corrected the problem. ( If I had the luxury of time, I would have had it checked out by an authorized installer. ) They removed the remote start system and the car is working normally again. I was releived that no other components were damaged. I lost a starter system (which was out of warranty), but they only charged me $129 for labor.