98 A4 electrical problem

I have a 98 A4 1.8TQM with about 130k. About a month ago I noticed an odd electrical problem that I can't figure out. The horn no longer beeps when the alarm is activated or deactivated, and the dome light
does not come on when the door is opened (nor dim/off when it closes). Otherwise the alarm works correctly and the dome light functions when manually switched on. I can't find in the fuse diagram where one fuse seems to address this problem so I haven't looked at the box yet, but I've got no idea where else to look.
Any suggestions before I go visit my mechanic?
Thanks, Eric
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and the dome light

Is it just one door that does not trigger the light? There is probably a switch inside the doorlock that can be faulty if it's just one door. Wather had gotten into the lock on my A6 and one pin on a connector was corroded.
Jone T.
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On Thu, 7 Dec 2006 00:24:32 +0100, "Jone T." <jone> wrote:

Unfortunately, no. It's a car-wide problem. Back lights, too.
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