I have a 2015 f250 I just bought from an individual I lost all of my parking lights.I still have blinkers, brake lights, headlights and hazards work. My parking/running lights are all dead . I went trough the trouble shooting process of checking fuses, checking bulbs anything possible. After finding nothing wrong I decided to check the BCM by bypassing the BCM and running a hot wire to the yellow and blue wire (I believe it was pin 10) and boom I had all my parking lights. So that being said I do believe my BCM is bad but everything else works. My question is since everything else is working except my parking and running lights would it be possible for me to temporarily cut my yellow and blue wire from the wiring harness and run a wire to my 15 amp upfitter aux switch for running/parking lights until I can afford to swap BCM and have it programmed? I appreciate any advise. Thanks in advance!

 

My brother has this same issue with his 2011 F250. From what I've seen so far, both should be the same from 2011 to 2016..

You can go the expensive route of replacing the BCM and having it reprogrammed.

Or, if the BCM ends up being the issue on my brothers, what I am going to do for him is bypass it but differently than you did. There is a built-in relay which is non-serviceable ( really smart decision by Ford ), so you would take the parking light trigger wire from the switch at the BCM and pigtail that into an external relay. Then add a hot wire from the battery ( Add an extra fuse here ) or if the BCM has that already you could pigtail off of that into the hot side of the relay ( and add a fuse to the other side since that would be fused already ). Then connect up the wires going to the parking lights on the other side of the BCM into the relay. This way you have an external relay which is serviceable. Additionally, by keeping the other wires in place you can more easily undo it if you swap out the BCM ( unplug the external relay and bundle or seal the ends of the wires - if you use a connector then even better -- if it fails in the future just plug the relay in and done ).

Another option, as you suggested is using the upfitter switches ( I was thinking of Aux3 since it is 15a on my brothers ) and they only have power when the ignition switch is on so it can be left in the on position without worrying about anything - although using the built-in switch would make more sense.

The downside is the BCM will shut off ALL parking lights if there is a short, where-as this solution something will get damaged - so I'd recommend an in-line fuse on the side of the parking lights as well. Then it is all external and you'll only need to swap out a fuse if something shorts.


Do you by chance have a service manual or wiring diagram for the BCM? I am looking for one so I can do the bypass if necessary.

 

I’d way rather use the existing switch rather than my upfitter switch. Putting a inline fuse is definitely going to be what I’m going to do so I don’t fry anything. I don’t have any of the schematics or a wiring diagram which would make fixing this issue so much simpler. I’ve been going off of random YouTube videos and really hard to read google images. You would think since ford had this bright idea they’d throw a guy a bone! I really like your idea of an external relay for many reasons, especially being able to use my factory switch and not wasting one of my upfitters! If I find any wiring diagrams I’ll send them to you!

 

I just found these going trough a different forum, hopefully these help!