2019 Ford F-350 side mirror wiring info

[bearcat77]

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!

[Marcm157]

Not sure if this will help. I used it to troubleshoot a problem with my mirrors.

[bearcat77]

Thanks. I’ve got a few more wires than that, but it’s something to start with.

[morleyz]

I know it's a little longer of a wiring harness, but it might be easier to just tie into the trailer harness for lights, turn, constant.

Also, the connector for power running boards should be attached the frame near the rear of the cab. Many people tie into this for courtesy running board lights.

[TCNashville]

You might have better luck posting that question here. https://www.ford-trucks.com/forums/forum279/ Lots of good info on this forum.

[bearcat77]

I do have the wiring harnesses on the frame, but those don’t do turn signals. And I did post on Ford-trucks.com. I’m covering all my bases.
Thanks.

[morleyz]

Originally Posted by bearcat77

I do have the wiring harnesses on the frame, but those don’t do turn signals. And I did post on Ford-trucks.com. I’m covering all my bases.
Thanks.

Right, my suggestion was to pick up the turn, lights and constant 12V off the 7 pin trailer plug rather than trying to figure it out in the cab and routing it out of the cab. The plugs on the frame could do the courtesy lighting.

[bearcat77]

Ah. Gotcha. I will check that out.

[bearcat77]

Originally Posted by morleyz

Right, my suggestion was to pick up the turn, lights and constant 12V off the 7 pin trailer plug rather than trying to figure it out in the cab and routing it out of the cab. The plugs on the frame could do the courtesy lighting.

So I did this, and it works, but now my truck keeps telling me a trailer is connected. I’m thinking may I need to hook into a different constant 12v. What do you think?