[SVXdc]

Originally Posted by rbizzle004

The factory amp problem was because I had the power antenna wire from radio hooked up to the power antenna wire from toyota metra harness. That wire is actually the remote turn on for the factory amp. So once I connected that and the remote wire from the HU everything worked out. The BRZ does not need a power antenna hook up.

Not quite correct...

The BRZ and FR-S (and recent Toyotas and Scions) have a pair of factory harnesses used for power and speakers -- one with 10 pins and one with 6 pins.

On the 10-pin harness:

• Pin #8 sends +12V power to the car's antenna booster amplifier (Subarus only).
• Pin #9 sends the +12V remote control turn-on for a speaker amplifier.

Viewing rear (wires side) of the car's factory 10-pin harness (or socket on rear of HU), the pin numbers run:

 4 3     2 1
10 9 8 7 6 5

On the BRZ:

• Pin 8 is PINK.
• Pin 9 is BROWN at HU's harness, and changes to GREEN at the amp's harness (transition happens at intermediate connector "HD2" behind the driver's kickpanel).

Subarus require that the pin 8 power antenna wire be connected. Without it, you'll have poor radio reception. This applies to the BRZ, as well as other recent Subaru models which have the Fujitsu Ten nav HU (Impreza, Forester, and Crosstrek). The factory HU provides +12V on that pin only while you're in AM/FM mode (both analog and HD radio). On Subarus, the power antenna wire is never on the antenna harness (that pin/wire is vacant on the factory antenna connector).

Since the BRZ and FR-S also have a subwoofer amplifier (for the door speakers), they also require that pin 9 have +12V whenever your HU is on.

The other Subaru models (Impreza, Forester, Crosstrek -- which don't have an integrated factory amp) do not have a factory wire at pin 9. The various OEM accessory subwoofers in those models do not use this pin.

Toyotas have the power antenna lead on their antenna harness and not on the 10-pin harness.

Bottom line: When installing an aftermarket HU, you'll need to make these connections:

BRZ:

• Do not use BLUE wire on antenna adapter (you can remove wire).
• HU's Power Antenna remote turn-on to car's pin 8.
• HU's Speaker Amplifier remote turn-on to car's pin 9.

FR-S:

• HU's Power Antenna remote turn-on to BLUE wire on antenna adapter.
• Nothing to car's pin 8.
• HU's Speaker Amplifier remote turn-on to car's pin 9.

Aftermarket wiring harnesses (Metra, Scosche, etc.) all seem to have one BLUE wire on pin 8, with a short loop tying that to pin 9 also. You can either:

1. Connect the long BLUE wire to your new HU's amp remote turn-on lead. This will power both the BRZ's antenna booster and sub amp whenever your HU is on.
   
   On the FR-S, the unneeded connection to pin 8 won't hurt anything. But if it makes you feel better, you can cut off and discard the short loop wire and its pin, and move the longer pin 8 wire to pin 9.
   .
2. Cut the loop wire off of pin 8, so you have separate wires on pins 8 and 9. Then connect to the respective leads on the HU's harness.