I just bought a 96 audi a4 2.8 quattro about three months ago. Thing looked and is in pretty good shape. I've been looking for random parts that need replacing on ebay and local junk yards, but not alot of luck.

But this issue i'm not sure what to replace, fix or just deal with.

A few weeks after buying it i realized the alarm likes to randomly go off. I did a little reasearch and reading of the manual and figured a few things out by process of elimination.
First off i know that it is a stock alarm. Which i dont know if it comes with or with or without a remote alarm switch, but i didn't recieve one with the car.
Second off i know the alarm monitors a few different things; the hood release, trunk release, radio, ignition, i think door locks and finally cabin motion. This model audi i believe doesnt monitor broken glass. so instead it monitors the movement in the car.
Well after trying many different things i have come to the conclusion that however it monitors the motion in the car, its broken. I dont know how it monitors, where the origin of the sensor is, or anything like that.

So before i get out of the car i have to disarm the motion sensor with a factory switch on the B-Pillar on the drivers side to prevent it from going off. It keeps it from going off but i have expensive electronics and belongings in my car.

How do i fix this? How does the sensor work? Where is it?
Also, does anyone know where a better place for online used or new affordable parts are for m year make and model audi?

thanks

 

If the sensor is anything like a 98 A4's, then it's sonic, not motion activated, and will detect breaking glass. If the windows or moonroof are left open (at all), it'll set off the alarm, especially if there's a close by traffic noise.

The sonic sensor I think is at the top of the drivers B pillar. There's little slots cut into the plastic cover, like a mini-grill.

The remote can be purchased that has the integrated key ("switchblade"). In order to set it a factory spare key is required to be inserted into the drivers door. I had the dealer do it, so learned the hard way years ago.

 

I see the slits u are talking about in the pillar. Now how do I take off the piller cover and not destroy it? And where can I find a replacement sensor?

Often when locking my car I make sure all the windows are rolled up all the way. So I don't see why it is tripping it. Must be a bad sensor.

My 96 Audi only came with a standard key. Is it possible to get a switch style with the lock and unlock that fits my 96 Audi a4? Just like I said in my first post, I don't even know if the alarm system is set for a remote.

 

Also it looks like there are the same slits in the opposite pillar. Is there two sensors? And while reading the manual it says to disarm the sensor with the switch on the pillar when you are going to leave a pet in the car. So I don't understand if it's a sonic sensor that detects broken glass, why disarm it when leaving a pet in the car?