Pontiac Repair: pontiac montana 1999 tail lights, mass air flow, pontiac montana

Question
First, let me thank you for providing this service.  You helped us out in July with a mass air flow filter problem.  Same car, 1999 Pontiac Montana.  Our problem is the rear lights (tail lights, turn signals, and brake lights) are intermittently going out.  We keep thinking we've fixed it and out they go!  I have read thru some of your answers on similar problems and here is what we have tried ...tightening the battery cables, replacing the bulbs, cleaning the connections.  The plug connectors going into the tail lights on both sides seem to have some scorch or burn type marks, not real severe though.  This may or may not be related, but when the lights went out the other morning the automatic sliding side door also wouldn't work, and sometimes when the problem occurs the radio/clock display goes in and out.  There was something in the rear that was beeping the other day, only when the car was in drive or reverse, not park.  I flipped some switch up by the rear view mirror and made that stop (never could figure out what those switches do).  Again, these things may not be related, but wanted to give you as much info as possible.  Is there a tail light circuit board and if so where would it be?  One last note, the light on the top of the rear window still works when the others don't.  Thanks for any advice you can give, really appreciate your time.

Answer
Hi Marsha:

I like repeat business :)

well those vans have issues with the tail lamp circuit boards burning out. either the sockets for the bulbs go bad of the connection between the tail lamp boards and the van wire harness melts. it's one or the other. This is a real common issue. even if there is signs of heat in the connector replace the harness end and the boards. as for the beeping noise if this has an auto sliding door option on it the contactor on the body for the door plungers is more than likely corroded. use a very fine sand paper and clean the contacts on the body and the plungers on the door and put some dielectric grease on the contacts and the plungers. that should fix the issue with the door. good luck :)