Interior Lights Dim, Horn honks randomly... NEED HELP!
 

Hey so I've had an 02 A4 Avant 1.8T Manual for about 10 years now. In the last 6 months I've had a super strange situation arise. While driving my dashboard lights will randomly dim then come right back and the radio does the same thing (sound & lights). Also the horn will randomly honk on its own. There seems to be no correlation of when it does this. When I took it to the Audi specialist they had never heard of it and when they pulled the codes the only one that came up was the Airbag light which has been on for about a year and reset multiple times.

The car has about 210k miles, and otherwise is in great shape and has been well maintained.

Have you ever had this problem? Heard of it happening? Have any fixes? Thank you in advance!