I recently picked up a '98 VDP and the stereo speakers only work on the left side of the car. Nothing works on the right when I change the balance to the right. I can't tell if the sub is working but I'd have to say no.

With the balance in the middle or all the way left, the sound is meh/ok, but not crisp (could be the old speakers).

How do I toubleshoot the no right side sound issue?

Thanks,
Dan

 

First, the bass...pull it out from under the rear deck. Almost assuredly its toast, sun baked and collapsed in on itself.
Easiest way to check the others is pull the door card...if original, you'll definitely be in the market for new stuff...hello Crutchfield....meter the connections.
You stated you have a bass, so you must have the premium unit...if not, please let me know and I'll upload the standard head unit diagram.

 

Thanks @Highhorse, I'll check the speakers first. I do get a quick POP from the RF door speaker when turning off the head unit so maybe that's a good sign it's not wiring.

Where is the power amp physically located?

 

Trunk, left side, ..and I'm not sure about the '98, but you should have a cd player also and both should be in a rack. They are separate, but integrated, through the wiring harness.

A popping noise sounds like bad cold solder joints and I would tend to suspect the head unit. If your not capable or willing to check it out, a local electronics store should be able to assist rather cheaply.
Also, disconnect the bass speaker and see if that popping goes away, it could be feeding back on the coil.