crazy electrical problem

[fastgerman]

I have an early '99 gti vr6 with 72000 miles. I have owned it since 70000 and the previous owner replaced the headlights with some high intensity aftermarket ones. The didn't work when I purchased the car, but after pulling the relay out and cleaning on the points a bit they worked fine until last night. I got into my car today and the alarm goes off as soon as I open the door. Note: I have no remote. Alarm engages when I lock the door. I get back from class and the alarm doesn't go off but the engine won't turn over. It honks randomly like the alarm is engaging while I am driving it and it will kill the ignition so I can't start it. It seems to correct itself then do it all over.........WHAT IS HAPPENING!?

[boschmann]

Those are really bad systems to work on. The best scenario would be that the sensor in the door that senses the key turn to unlock position is bad.

[veedubmechanic]

When the alarm goes off try wiggling the key in the ignition ( if the alarm stops or if you are alble to start the car than replacet the ignition switch electrical portion.

Try unplugging your vacuum pump control module in the rear hatch area. Pull back the carpet on the right side and there should be a foam box, open it and umplug the connector (also check for corrosion). You wont have power locks, but see if that does anything.
If the alarm stops going off than replace that module (about 450.00)

If that doesnt do anything I would try replacing the door latch.

Last of all the alarm control modules do go bad in these also but are the least common there to the left of the instrument cluster behind the lights switch.

[fastgerman]

i took it to a foreign shop here and they replaced a ground strap and 'rewired the alarm'. Yeah right, I'm sure that would take more than the 4 hours they billed me. They also told me they replaced the tail light holder...Now I don't have any tail light on the left and my power locks are gone. Plus my lights keep going out. I clean the points on the relay and they work fine...for now. What a mess!!!!!!

[veedubmechanic]

Theres a known problem that the taillight harness in the hatchbacks get water on them from leaking inside the car and corrode. But if all you did was clean the contacts on the relay than Your harness is problably ok. (since they replaced it)

[fastgerman]

It's the headlights that keep going out though. The previous owner put some high intensity bulbs in there. The shop took out the vacuum module and said it was melted due to the headlight bulbs.... I haven't been over to see it yet but they say that is why my locks are gone and they also said that it would affect the lights. I want to get stock bulbs but the entire headlight fixture is aftermarket. Will stock bulbs fit in there?

[veedubmechanic]

The headlights are in no way connected to the vacuum pump control module. Aftermarket headlights cause the harness to melt that plugs into the bulb. installing upgraded headlight harness readily available on ebay should help that. ( use vw headlight harness in search)

[fastgerman]

I got a brand new relay and it did nothing for me. I will look up that new headlight harness to see if I get any results. Thanks

[schlyguy]

I was wondering if you got to the bottom of this problem. I have something very similar going on with a 94 GTI. My radio will cut out for 2 or 3 seconds, every 30 seconds or so while driving. When the radio cuts out, the turn signal cuts out. The radio and turn signals cut out more often when the rear window defrost is on. When I get in or out of the car, the horn beeps once. Any ideas? I'm thinking maybe a bad relay, because the problem started all of a sudden.