My buddy is putting in an aftermarket radio in his 97 xj with the infinity speaker system ( with factory amp under seat). So we bought the correct wiring harness connected them up matched all the colors and all that. When we plugged it in it powered up and everything but no sound comes out of the speakers. Does the stock amp mess with something on the aftermarket radio? Were putting one 12 inch sub in with an amp. So do we need to bridge the factory and sub amps in order for the speakers to work? Anyone had this problem or know what the issue could be. Thanks
Sorry if this post is in the wrong category.

Yes the factory amp messes with aftermarket speakers. Everything else works, but no sound comes out. I dont remember the solution but there are a couple links online if you do a google search.

The speakers are stock but the headunit is aftermarket.