I bought the car with one speaker working. I discovered that there was no amplifier, so I tested each speaker and both channels out of the stereo from the trunk, and all work fine. I got an amp off ebay and it works fine.I have tested it in my buddies 735, so I know it is good. The amp has constant power on the black connector, it just seems like it is not getting the turn on command from the radio. I have found so far on the net that the white wire at the amp should be the turn on signal from the radio, but I have tried injecting a signal with no luck. I am getting ready to buy an aftermarket amp and chuck the stock equipment. The white wire is on the white connector 3rd on the bottom row from the fuse side of the map. I have checked for ground and voltage with the radio on and get neither. Any help? The amp is a blaupunkt 7 607 254 551 040. I have good power, audio in, good speaker outs, a good amp, what am I missing? I do know the stock cell phone is disconnected, I found it under the rear seat. Could that be playing a role in this?