Audio Systems: No Sound, chevy tahoe, bose system

Question
No problem Peter I appreciate your help. I have all my speakers hooked up to the deck, and the sub is hooked up separately through the amp. I bought a wiring harness for the deck, that connects to the stock deck harness. I'm sure your familiar with this type of aftermarket harness, the harness just makes it easier to identify what the power or ground wires are, which one is the front left speaker or front right and so on. It makes it so I can hook up to my aftermarket deck with out having to splice into the stock wires. All in all the deck and amp are hooked up properly. Could a bad battery or alternator cause the problem? Thanks again. Jacob    
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-----Question-----
I have a 2002 chevy tahoe, I recently took out the non Bose stock deck and put an aftermarket deck and amp in. I have done these type of installations before. But im running into something I have never seen. Every now and then when i start my tahoe up no sound comes out of the speakers, but I can here the bass line coming out of the sub but nothing from the main speakers. I don't have a Bose system so i know its not because I haven't bypassed the stock amplifier because there isn't one....or is there? What is causing the loss of sound. Looking forward to any help you can give me. Thanks  Jacob
-----Answer-----
Sorry Jacob but I need more info, are you running the speakers and sub from the same amp as you seem to be implying? how have you wired the speakers? how have you wired the sub? Remember I'm not seeing what you can so I need to be spoon fed.
Peter

Answer
Hello again, :-)
OK lets forget the amp and sub, as there doesn't seem to be anything wrong there, it's working and it also implies the power is stable to both radio and amp as the radio provides the sound for the sub via the amp.
The alternator is not in the equation as it only provides charging to the car's battery and is not connected directly to any part of the car other than negative side of the ignition warning light and if that goes out after starting then that says alternator is charging ok.
Battery will only really play a part if running large amps when you should really be looking at a separate amp battery and a split charge relay. Try with the amp disabled, (just pull the fuse) and see if the head unit works ok on it's own, if it does then it might be a case of the amp dragging the radio down to below operating voltages, (see separate battery) or too thin a power lead on the amp, which as you know should be a heavy begger direct from a fused connection on the batteries + terminal.

Speakers hooked up directly via an adaptor harness so shouldn't be any problems there and all 4 cutting out together is a no-no and as it's "every now and then" it will not be a connection problem, they tend to work or not so.... we are left with...
Mute lead for phone?
Faulty radio, (output amps), best checked by swapping for a know good one, even an oldie will do as long a it has the same connections as your new one (ISO DIN?)
Faulty adaptor harness?
Speaker plug or socket loose?