All I have is a deck and cd changer. I was hoping for a starting
point like where to check if it is a wiring problem. Or if it could be my alternator is going out

Changing out a battery or alternator should not have any effect on causing or curing a problem with certain speakers not playing.

If your system is factory original, it is probably a head unit with built in amplifier playing directly to speakers. If one (or more) speakers is not working or works intermittantly, the problem has to be in one of three areas: a defect in the head unit itself; a defect in the wiring between the head unit and the malfunctioning speaker; or the speaker itself.

I would guess 60% head unit; 30% wiring; 10% speaker as the likelihood of being the problem.

tanstaafl.