Maybe someone have a BCM input/output electrical schematic?
I need to find a signal of lights: central stop (top of cabin), front left and right turn signal, 12v permanent after ignition.
The second question is about tow hitch electrical system. When I should have power on pin 4-12v baterry power (7-way plug)? After ignition (no engine running) i checked it by electric meter and there was no electric voltage.

 

I believe it won’t put power out until it detects a trailer plugged in.

 

How the car detects it? I also used a 12 V light bulb for measurement with no effect.

 

When the truck detects trailer tail lights or brake lights it activates 12v power to the trailer hitch.