Electrical Glitch Assistance Requested

[McCullough]

I'm having a problem with the driver-side door electronics on my US '99. Passenger side is OK.

Everything seems to point to the fact that the alarm system seems to think that the door is closed at all times, even when it's actually open (except when I actually am pulling on the inside or outside door handle).

When I lift the door handle on the inside or the outside, the window drops a few millimeters as it's supposed to, but if I oprn the door and release the handle, the window goes back up (as if the door was closed).

In addition, if the key is in the ignition, and I open the door, the warning gong sounds when I lift the door handle, but stops immediately when I release the handle, even if the door remains open; if I pull up on the handle with the door open the warning gong starts sounding again until I release the handle.

Everything else seems to work OK: windows work OK with the inside switches, open and close when holding the key in the door, open a couple of inches when releasing the convertible top latch, etc.

One other symptom I encountered while testing: if the door is open and I press the key to remotely lock the car, I can hear both doors lock, then immediately unlock and I get two beeps from the alarm rather than the single I would expect. Seems to indicate that the system thinks the door is closed, sets the lock, then realizes that the door didn't lock so unlocks and sounds two beeps indicating an error.

I've removed/reset the appropriate fuses, disconnected the battery for an hour or so, and opened and reset the door wiring connector box in the 'A' piller after spraying both sides with contact cleaner.

Is there some kind of switch or sensor that tells the alarm system that the door is open or closed? The wiring diagram shows switches for "door contact," "lock," and "safe contact" (what is that?), but I don't see any PET parts listings for any door switches other than the handle microswitch. Could that be the one?

Any other tests I can try or ideas about how to fix?

Thanks.

--- Tom

[Loren]

Item 5 - microswitch

[McCullough]

Item 5 - microswitch

Thanks, Loren. That's the first thing I thought of. But would a failed microswitch precipitate the other faults I'm seeing? (e.g, alarm error double-beep when locking an open door).

The handle switch *seems* to work OK since the window drops when I pull it and the window goes back up when I release it. The ringer is that the system doesn't appear to know that the door is actually open so the window should stay down. Is one of the functions of this microswitch (key #5 in your diagram) to know if the door is open or closed? If so, then I agree with you and I'll get a new switch.

Thanks.

--- Tom

[Loren]

The only way to tell for sure is to get the alarm fault code(s). You can do that with a PST2, PIWIS tester or the Durametric Software. A PST2 will allow you to test each individual component of the alarm/central locking system.

[0586slb]

Tom,

The microswitch Loren refers to is the switch to activate the window lifter. The switches to detect door closed, locked, key turned etc are all in the door lock module. Module being the operative word, all the functions are carrried out in one lump of plastic. Part number 8N1 837 015C. To the eagle eyed, this part number is for the door lock of a LHD Audi TT. Being electrically minded, I would open the module up to see what was what, but if you haven't the confidence, I'd verify the part number with your OPC and see if you can get it cheaper from an Audi centre.

[Loren]

:oops: ... my mistake I was thinking this was a different post