My girlfriend's 90 Accord EX has some electrical issues.
1. The door ajar light stays on(all 5 doors)
2. The stock stereo has a mind of it's own. Sometimes it comes on full blast when turning the ignition on. I checked to see if it was a cold solder joint on the faceplate board(volume up+down switches) but they were OK.
3. The pass. side seatbelt retractor sometimes doesn't actuate. Is there a switch in the door latch that controls
this?

The car is a totally rust free Florida car with 97,000 miles. I would like to fix these bugs before we put it up for sale. Any help would be greatly appreciated.
Thanks,
Mike