Installed pioneer stereo and no sound out of middle speakers in 1997 chevy suburban?
You need to turn on a factory amp that runs the rear door speakers. It’s not necessary to go the the actual amplifier in order to do this. Just go back to the radio wiring and make sure the factory amp turn-on wire is connected to the Pioneer’s blue/white amp turn-on wire. The factory amp turn-on is usually in the “power antenna” location in the stock harness; GM normally uses a pink wire for this function. If you used an adapter harness, then the blue wire in the harness should be connected to the blue/white wire in the deck. You don’t need to do anything special to use the stock amp with your new head unit, except for connecting the wire to turn it on.
