I recently purchased an '88 convertible. The surround sound system does not work. The guy that I bought it from said that it was intermittent and then failed. The under dash speakers do work. The door speakers and headrest speakers do not. The indicator lights for the surround sound controls do not light up. I have the checked all connections and they seem to be good. I know that there is an amp behind the driver's seat. Do these tend to fail? Any troubleshooting help would be greatly appreciated. Thanks!!

 

Mine didn't work on my '90. Take the amp out from behind the drive seat, under the security cover. IT's the small shiny silver rectangular box. Unplug the connector.
Verify the fuse in the amp is good.
Verify that the amp solder joints are good. You have to take the cover off to do this.
Look for problems with the wire loom.
THere is a connector pin out in the fsm. Verify that the +12v connector still supplies power.
The plugs for the headrest speakers are under the seats. Make sure they are hooked up. My wires were grey.
Good luck.

 

More info. If someone has replaced the head unit, then they need to patch the "on" wire for the new HU into the amp on circuit. I think it's on the rear plug, but it's been long enough I forgot the color, maybe brown/red. If that isn't patched then the amp will never turn on and the controls/sound will obviously not work.

A search would reveal a pretty long post from about a year ago on this topic.