Smell of burned wires and AC display and radio malfunctioning

[KirilR_Park_Avenue]

While driving there was suddenly a smell of burned wires and a quiet very high pitched sound coming from behind the IP. The AC display is now flashing (alternating between bright and dim), and the radio display doesn't work. The radio and AC themselves work, however the power antenna is constantly extending and retracting. Strangely, before that happened, the passenger side AC sometimes turned itself on and - without being controllable - slowly went to the hottest setting. Don't know if those problems are related. Does anyone know what the problem could be? I'm thankful for any ideas. It's a 1996 Park Avenue.