RudyP

The alarm in my 1996 C4S will occasionally (every few months) just start going off for no reason. Car is garaged and this happens when no-one is near it. Annoying at best when I'm home and I'm worried this will happen sometime when I'm away and drain the battery or **** off neighbors substantially.

Any ideas what it might be?

R

jg291446

There are a few threads on this topic.

You should check the switches in the hood and doors in case they are worn.

Did it rain a lot recently? if water leaks under passenger seat, your Alarm control unit may be defective.

In Rennlist threads, you can see that the radio can be the cause. I don't know why so maybe someone can chime in. "The green wire is intended to operate much like the rest of the switches in the alarm system. If the factory installed radio is pulled from the car the green wire connects to electrical ground and provides an input to the alarm control unit. If you have an aftermaket radio the green wire should be disconnected and isolated (taped up?)"

https://rennlist.com/forums/993-foru...no-reason.html

https://rennlist.com/forums/993-foru...m-problem.html

bjornebo

I had a "green wire" issue when I bought my C4S. A PO had replaced the original radio with a CDR 220. The green alarm wire looked like a ground and the installer connected it that way. The symptom was that the alarm LEDs on the doors double flashed instead of single flashing. When I disconnected the wire, the alarm LEDs operated properly (single flash). In any case, this did not cause my alarm to sound.

J.B.H.

If you have checked the points others have mentioned you can try this. I had an 86 BMW with the same issue.. It turned out to be the fuse.. The fuse was not snug in the fuse block ... Make sure the fuse us properly seated or change it altogether.

hoggel

If the radio chassis green wire is solidly connected to ground when the car is locked using the fob the alarm system will show a fault (double flash) and not monitor that circuit to trigger the alarm. If the wire is not grounded when the car is locked and then touches ground with the alarm on, the alarm will sound.

Ish993

I also had this issue and it was related to the anti-theft system on my radio

bjornebo

To ensure that this would not happen, I insulated the bare end of the cut green wire with electrical tape. I have had no issues with the anti-theft system since then.