My truck has the prewired plugs on each side of the frame for the courtesy running board lights. I'd like to connect some LED lights under the doors, and I'd also like to connect my rear work lights to this circuit so all around the truck is lit up when I press the unlock button. I think it would look really cool.

It would be great to have all of these lights also connected to an upfitter switch to turn on whenever needed.

I know it's possible, and I've searched but I can't find exactly what I am looking for.

I think I would have to get power from the battery, because I'm worried about all the lights affecting the BCM when they are triggered by the courtesy light circuit.

All the lights are LED and should be just under 5.5A total.

Can someone please help me with a diagram to trigger these lights with both an upfitter and through the circuit with power coming from the battery?

 

The factory connectors for the running board lights are hooked into your interior lights. They will turn on whenever the vehicle is unlocked by the remote, the doors are open, or when you press the dashboard dimming switch to turn on the dome lights.

I have a 5 foot strip of LEDS illuminating each running board, and the running board connectors are also wired into two 7.5 foot long LED strips that are mounted under the rails to illuminate the bed. Everything turns on at the same time. If I need to illuminate my bed, I just press the dimmer switch until it turns on the dome lights.

If you want to control yours separately, you can use the upfitter switches. They're already powered and fused, so you don't have to use a separate connection to the battery. If you don't want your dome lights to turn on at the same time as the other lights, you'd have to put a blocking diode in the circuit so that the Upfitter switch supplied power doesn't feed back into the Ford running board wiring.


Here's the Ford Schematic for your switches:

 

Thanks, that's gives me a couple ideas to start.

However the one thing I am concerned about is pulling power from the dome light circuit. I've read that if the computer reads too much power running through it will shut down that module.

Do you have a diagram like that to help me wire a relay with the dome circuit as the switch and power from the battery?

 

What year did the BCM begin?

 

I'm not sure but it seems like what I've read about is 11 and up. Mine is a 14.

I can't find anything now but I've definitely read about people tapping into those pre wired plugs under the cab and having problems with the dome lighting circuit shutting down.

 

My 99 has the wires running down the back of the inner fender for running board lights as well. If yours is like mine, you should be able to unattach it from the inner fender and pull it back up into the engine compartment. Then, use it to power the switch side of a relay- then you can run a power source directly from the battery to the relay, then from the relay to the lights you want to add. This way, the only amperage the running board light plug will see is the minuscule amount it takes to close the relay- which would be less than the factory running boards would have pulled.

 

Yeah that's what I was thinking. What would be the difference if I pulled the wires back to the engine vs splicing into them wherever they are along the frame?

 

OK... I'm working on a 16 f650 truing to do this. I have a plug on the driver side,but can't find one on the pass. side. Also, are these plugs only for courtesy lights or running lights as well.

 

The connectors on the smaller trucks are only for the courtesy lights. Maybe someone else can chime on the F650