Head unit pinout abbreviations
| Pin Notation  | 
			Pin function | 
|---|---|
			Power pins | 
		|
| BAT | Battery+ (12V direct from Battery). | 
| GND, GROUND | Chassis Ground | 
| KL.15 | Ignition powered. +12 V with the ignition key is in the ACC or ON position. | 
| iLLUM | Light-on signal or backlight adjustment. +12V supplied to light-on pin of head unit when tail lights ar turned on. | 
| ANT OUT | 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 | 
			Misc. pins | 
		|
| MUTE | This pin is used to silence the audio, earthed by some other external components that is connected to the radio. | 
| GAL | This pin is used in some radio equipment to automatically boost up the volume. It needs the output from the speed sensor. | 
| CAN-L, CAN-H | CAN on board diagnostic bus | 
| K-Line | K-line on board diagnostic bus | 
Mercedes Comand Harman-Becker





