yea im a bit unsure of what u mean? But i just thought about something... if its an aftermarket HU... and u have the RCA's connected into the back... did u make sure on ur HU that it has those pre-outs selected and turned on? because if you dont most likely u will not get anything going to that Amp... Its the same deal with an Amp for a Sub...

 

the amp is hooked up with RCA
the speakers are directly hooked to the HU
the amp and the sub work great but thats it, no speakers from the HU

P.S What is a good price for dynamat?
I might as well do that while most of my interior is apart

 

Ok so what did you unhook that made them start working? The RCA's? If so, there may be a short in them or it's grounded somehow. Could even be the amp. Try this: Unplug the RCA's from the AMP with them still plugged into the headunit. If the sound still cuts out, then it sounds like it's a bad cord, or you have a screw through it or something. If it starts working when you do that, then something is messed up inside the amp and it's grounding out the RCA's or somthing.

 

Check the wires ur best bet is to take a speaker out and take out the head unit and wire the speaker directly from the HU wireing harness to the speaker and see if it works. If it does then its ur speaker wires, if not its ur HU and the line output for the speakers could be blown

 

I've tried unhooking the RCA with no avail, i haven't pulled the speaker and HU yet but i'll try this weekend