Since Kenny gave me the Alfa, I’ve had about three or four head units, connected to the two Kenwood KAC-7200 power amplifiers under the rear seat. Over the years, I’ve managed to screw up the wiring, so I decided re-wire it correctly, since I put in a freshly rebuilt 65 amp alternator (the stock alternator is 45 amps).
The first thing I did was connect two 10 gauge wires from the alternator to the battery charging circuit. For the power amps, I ran a new 12 gauge wire with an inline fuse from the battery to a relay.
This relay is switched on by the head unit when it is powered on using the wire from the Clarion that provides a positive 12 volt signal to the amplifier’s turn-on input.