The Metra branded ISO-Audi harness has a wire for "AMP turn on signal". When this is disconnected, the rear amp doesnt turn on, no sound to rear, fronts fine. When it is connected to the 12v Acc line (no dedicated turn on signal on the HU), the rears are on, but the fronts are muted?
However I should point out the signal from the head unit is already amplified (I put the volume down really low to test the rears).. what can I do to get out of this mess?
Matt