I have a 2019 F-350 Lariat with the power fold, heated, tow mirrors. I want to tie in some led running board lights. The running board lights have the courtesy on-fade off feature, along with constant on, and sequential turn signals. I need to find the parking lights wire, the ground wire, the turn signal wire, and the door assist light wire. There must be 20 different wires feeding into the mirror and I can’t find a current Ford wiring diagram to save my life. I will attempt to get a multimeter and check wire by wire if I need to, but I’m hoping someone has already attempted this and can name the four magic wires for me. Thanks!

 

check to see if you have the speaker looking plug on the frame rail near the back of the cab. if you do, just get the metra speaker plug and plug them in... easy peasy..

 

Do you have the tailgate trailer assist light? If so, you should have the running board light connectors on the frame.

 

I do have those plugs on the frame, but since there are only two wires feeding into them, I assumed that wouldn’t do the turn signals- they would just be on or off. Am I wrong?

 

Those won't do turn signal. They will operate just like the OEM running board lights.

 

So I ended up running wires to the back of the truck and tying into the wires for the 7 pin tow connector. That worked, but now the truck thinks a trailer is attached. If I find a different constant 12v wire to connect to for power, will that fix it, or will any connection to any of the wires associated with the towing harness trigger the trailer connected message?

 

Bearcat - did you figure this one out? I've installed running board lights too and I used the frame mounted connector to activate the courtesy light but now I need to wire up my turn and running lights. I was hoping to find a wire in the cab for this.

ideally, I want to install some switches (inside console?) so I can override when these are active. I tow a large 5th wheel so I think the turn signal feature would be good while towing but don't necessarily want it on all the time.

Thanks