Thaaank you very, very much for the info!
The idea is to use the OE front fog lamps light switch (pins) to turn on the rear fog lamp; those are mandatory in Europe, where I imported the car.
I was looking at the Starkey YouTube video for front fog lamps. There they show how to splice cables into the original switch, and it seems they are using this 13th pin to power one of the relays for front fog lamps. The guy installing the lights was talking in the comments that this pin 13 connection is necessary for 2013-14 mustangs. I was worried if that was something important and delicate (some CAN line or something).
One thing that is confusing me a bit, is the fact that when I activate the switch right now in OE state of things, the indicator doesn't light up (from the diagrams I would assume it already should).
It will now be easy, relay in the trunk switched by GND from pin5 of the switch, feeding 12v off of rear lights "brain" connector, powering the lamp itself and the indicator LED on pin10.
Thanks again, cheers mate!
Thursday, September 18th, 2025 AT 2:06 PM