I have a 98 olds bravada and the speakers have been working intermittently. The driver door speaker always works and the rest work sometimes. Mostly the one that will come on is the passenger door speaker, but like I said, sometimes different speakers work, sometimes all speakers work, but at least always the driver door speaker works. I replaced the head-unit twice and am certain now that is not the problem. A guy at Circuit City said it could be condensation on one of the speaker terminals because it seems that running the heater makes the other speakers work. Also, they usually tended to work much more often in the summer when the car was parked in the sun. Does his theory sound correct? And if so, what can be done to fix the problem. If not, what else could it be? Thanks for your help.