I have a 1999 Pontiac Grand Prix GTP - got about 186,000 miles on it. Never seen a garage (as in, always stored outdoors) Unfortunately it's a rust bucket, but no other choice. Here's a list of issues:
HUD dims and goes out and comes back on at random
Tachometer - will be reading normally and then will just go to zero, and when it does, the TCS Off Light comes on. It will often go back the other way and be working again on the same drive.
Clock - the numbers will often get wigged out or go blank. Radio, CD et al works fine throughout.
Heat and A/C Fan - not working at all - either in Auto or in manual. There is still heat and cooling going on, as I can feel it coming out of the vents but no force behind it. And this is no good since I live in the northeast, and soon the blower and heater will need to be 100% for safety if nothing else.
And the last weird problem is the rear speakers go dead at random. It's to the point where I'm surprised they are on at all.
What is the common denominator to all of this?? I've read it could be the Blower Resistor, the Resistor Pack, the blower motor resistor, or the Ignition switch. I'm not totally qualified to repair any of this but if need be I can. Can't afford to take it in to the dealer for what's sure to be thousands of dollars.
Any ideas?