OEM Radio question
 

I’ve purchased a D1 OEM Radio off ebay, it had "GB 4x4 radios" service sticker on it, seller said it was tested before selling and is in working order (hopefully). I Installed it recently and when trying to play anything, only when the volume is all the way up, I can barely hear music from one of the speakers. Aftermarket radio previously installed with converter-harness was putting out sound through those speakers without issues (minus tail door subwoofer). Logically thinking, it means the OEM radio is not in a working order, or could you suggest what to check before I send off the radio to be fixed, maybe there's an OEM amp somewhere remote, or some other cables I should check? Any input would be greatly appreciated. As always, Thanks!!!

OEM amp is under the passenger side kick panel. Sub amp is in the cargo door. I'd check the amp under the kick panel, probably bypassed because it's not needed with an aftermarket radio with its own amp.

Grab the Electrical Troubleshooting Manual from the link in my sig ( etljyy0x.pdf yy=year of your truck ). In fact, grab all the manuals.

As always - thank you guys, will try to troubleshoot the damn thing this weekend! :)

hit the binnacle volume up switch to make sure its not muted that way

amp can be Under the passenger seat for 94/95, on the passenger kick panel for 96+, or under the drivers seat for the 98 LSE package