Car alarm comes on 10 minutes after I lock the car

Ok, I have a 1988 S4, The car when I bought it back in 2012 had an after market alarm system in which I had removed do to the fact that I had to dis-connect the battery every time it went off for no reason. So I had the factory system re-connected. Every time I lock the car, the alarm would go off 10 to 15 minutes later. it would come on for about 30 seconds. One thing I did notice is that it comes on more often when the car is hot during days with temps above 70 degrees. How can I fix this and what should I be looking for?

1988 S4 (favorite)
2000 996

Connectors and ground connections are always the first thing to check. Also check the door light switches in the doors.

If you don't have the wiring schematic, you can download it from

www.ligeti.com/928/

That will show all the wiring and connectors to check out.

Best regards,
Rich

Thanks for the info, we'll give it a try