I have a 92' lx convertible with a factory amp in the dash. i bought an after market head unit and i hooked it up and the unit turned on but no sound came from the speakers. i heard that you have to bypass the factory amp and i need to know how.

 

there is a amp under the deck that looks like a large octaganal box with a bunch of holes in it and 2 hrns going in and out. Follow one of the hrns's up behind the glove box and there will be two standard for speaker hrns(8-pin) plugged in. With the radio on, disconnect these and all sound should stop. use the side of the hrns that is towards the speakers and you have just bypassed the system.