Hey gents,
I have a 2012 Ford F350 XL with factory installed upfitter switches. bought a set of bed lights off amazon and ran the wires to the inside of my cab. Going to hook up to #4 fitter. I have read all the wiring and specs and do have the correct wire. I had read that when the Key in on accessory or run that when you flip up the switch you should get a yellow light showing power to it?. Well, after wiring up the little bed lights nothing. Sooo,,,, I called and went to the ford dealership where I bought the truck to see if they could do a test why the upfitter has no power. Arrived at dealership at 0-dark-thirty and first thing the service tech says is did you install these, who told you then aren't working and that a fuse is not covered under 3/36, also it costs 90 for diagnostic test. My 3/36 goes out in Nov. Tried slowing him down and showed him the original window sticker when I bought the truck. Went to the waiting room and 15 minutes later, he and another service tech which gave me his resume in 5 minutes and he is an expert on the upfitter switches and that they have power but you have to hook something up to them before the yellow light will come on. Left the dealership with no satisfaction. Went home and re-checked the upfitter wires. #4 Brown and three others above the steering column. connected the power wire to the brown #4 and grounded to fire wall metal. Started truck and still Nothing from the bed lights and no yellow light on the fitter switch. I know the bed light strands work, tested them on the rv battery in the garage when I bought them. really stumped now and I have read a lot of post and threads about the fitters and down loaded the diagrams. I did check the fuses and relay and made sure they were tight. Really sad they put these things in and basically useless. Any help or advice from anyone is appreciated.
Confused

 

Don't know if the years differ but might yellow lights lit up anytime I flipped the switch. Hooked up to anything or not. I would go to a different dealer

 

Led in switch is independent to what is hooked up, it just turns on a relay which is what the end user needs to configure supply the ground and source power.
see post 21 this thread Upfitter switches on the 2011
Chuck

 

Correct - if you are getting no yellow light on each of the Upfitter Switches with key on/Switch On, check fuse F44 (10A)... that powers the switches/LEDs and their respective relays, which would also stop your accessory (bed light) from working.



Upper left of main diagram - if it's O.K., then you have a wiring problem in the upfitter switch option!

 

Here's the whole diagram if you need it...

 

Gents,
I do appreciate the replys on my upfitter situation. I will have to recheck all fuses and connections. Just a shame dealerships won't take the time to help you.
Again Thanks.

 

Hey Gents,
I finally got my up fitters working. Thanks for all the advice and diagram and layouts. Found a 10a fuse blown. This is the first time every using my switches. I don't think they have worked since I bought the truck in 2012. Also, the dealer service tech is wrong by saying they only light up when something is attached to them. I turned the key to accessory and yellow light came on with nothing attached. Anyway, again thanks for the help and I included some pics for the completion. Maybe this will help others also.

 

Glad you got it working... nice lights too!

 

trying to wire reverse camera and want ability to view when not in reverse so reverse light hot wire is not an option. Was thinking of using upfitter switches and have seen videos showing wires near cab next to firewall. Crawled under back and saw theses two plugs with caps on. The little round plugs are rubber plugs to weather proof the hole. Thought these might be terminated with plugs ready to use upfitter terminals in the rear but didn't know. Thoughts on what these are?

 

I have no Idea what those wire connectors are, sorry. My F350 is a 2012 and the four upfitter wires through the fire wall are under my hood behind the engine fuse box. I took a couple of pics of the upfitter wires for reference. Sorry again I have no idea on the plugs, you would probably have to look at a wiring layout. Unless someone else has suggestions, Hope the pics Help,,,, good luck.

 

The wires you show (at least on my 2005) are NOT upfitter wires, but firewall pass-through wires with the other blunt ends near the fuse box for owner hook up if needed. I believe the upfitter wire blunt ends are somewhere above the gas pedal (more or less), I don't believe the plugs under the back of the truck are connected to upfitter switches.

 

Those at the back are for 5th wheel hook up, and I think to run them into the bed if you need them. So, you won't gain anything for the upfitters.

If running something to the rear, you'll have to run the wires. Make sure to use something to protect the wires.

I ran it down the frame rail for my auxiliary backup lights.

Those in the engine do look like the pass through wires.

 

Thank you!