On the 14-pin connector for the power and illumination connections (and speakers in other Subaru models), pin #6 is +12V Battery/constant-on. The term "Back Up" is meant like memory back up, not reverse gear lights.
Also, in most Subaru models, pin 14 is used to provide +12V power to an antenna booster amplifier. Very few models have a motorized antenna.
Radio reception will be degraded noticeably if the voltage to a Subaru's antenna booster amp falls below 12.0 V.
Head unit pinout abbreviations
| Pin Notation |
Pin function |
|---|---|
Power pins |
|
| B+ | Battery+ (12V direct from Battery). |
| GND | Chassis Ground |
| ACC | Ignition powered. +12 V with the ignition key is in the ACC or ON position. |
| ANT+ | Power for Electric Antenna. Output +12 V (maximum 150 - 300mA) |
Audio pins |
|
| FR+ or RF+ | Front right speaker out |
| FL+ or LF+ | Front left speaker out |
| RR+ | Rear right speaker out |
| LR+ or RL+ | Rear left speaker out |
| FR- or RF-, FL- or LF-, RR-, LR- or RL-, SGND | The corresponding speaker ground |




