The radio receives power from the 10 Amp radio fuse is located in the rear fuse block. The radio uses this Hot at All Time circuit to power all internal circuits and the VF display. The Turn on signal for the radio is received through the 5 Amp Radio/Phone fuse located in the rear fuse block.

Backlighting for the radio buttons is controlled by the Panel Lamp Input circuit and the VF dimming is controlled by the Display Dim Input Circuit.

Ground for the radio w/o U99 is redundant until S209 which continues as a single circuit until G202. For radios w/ U99 there is only a single ground circuit from the radio.

All speaker circuits come from the radio

All speaker circuits from the radio pass through the audio amplifier and then to the speakers.

The remote CD changer receives Hot At All Times B+ voltage through the 10 Amp CD/Phone fuse located in the rear fuse block.

Ground for the remote CD changer is through G202

There is a right and left channel audio output to the radio that use a common output to the radio.

The remote CD changer is controlled by the radio through the serial data E&C circuit.

The audio amplifier receives a Hot At All Times B+ voltage through the 10 Amp radio fuse in the rear fuse block and is redundant from the rear fuse block to the amplifier.

Ground for the audio amplifier is through G202 and is redundant until S206.

The amplifier looks for a turn-ON signal at the left rear speaker inputs (+ and -) from the radio before turning ON.

The amplifier uses the diagnostic data line (DDL) to adjust the radio input volume to keep the amplifier under 10 % distortion.

The antenna module receives B+ voltage from the radio when it is turned on. This circuit travels through the IP fuse block and the rear fuse block.