I have an interesting problem. Truck is 2021 F250 Platinum, originally with LED headlights. I had my truck extensively modified and for a number of reasons we used Anzo 2015-2017 F150 lights on the front. This isn't material to the problem at hand, but the entire front end was replaced with a custom hood, etc and it is only designed to fit that shape headlight, in case folks are wondering why. However, this creates a problem in that the high beams don't work any longer. Anzo support said:

"The issue you have would require ECU or BCM changes, you might look into ForScan if it is available for new Superduty. The issue is that Ford uses both top and bottom beam as both low and high beam for the 2017 and up Super Duty's. The F-150 headlight is designed to have the top beam as the low beam and the bottom beam as the high beam. The system is not recognizing this and not working correctly. "

I also don't have fog lights up front anymore. I looked at the Spreadsheet for Forscan on 2020+ Super Duty and I don't think there are any BCM tweaks that will really do what I need. At least, none anyone has documented yet. So, some of my initial ideas (some of these may be terrible or dumb).

1.) Figure out if I could use the fog light circuit, since I don't have fog lights any longer. That would provide an available button for it. No idea where the wires are for that now, though. Need a shop manual / wiring diagram, and I am not even sure this would work. Might be too much current (2x55w bulbs, so that might need a relay and separate circuit, which wouldn't be too bad if I knew which wires were fog lights and how that might work).

2.) Miracle Forscan tweaks. Unlikely going to work for a while until people fully explore the new super duties with Forscan. Maybe Ford VCM can do something, but that is going into uncharted territory.

3.) The "i know this will work solution". High beams are just 12V H7 halogens. Wire them up to a circuit myself and run a switch somewhere convenient in the cab. The least desirable path, but high beams are rather useful and this would be fine with me if there isn't a more clever solution.

4.) Your suggestions and ideas here. I have no real idea what I am doing, just thinking starting from a place of limited knowledge and trying to find a nice solution that is ergonomic and reasonable. I thought this would be an easier to overcome problem. Did we just miss something really obvious with the wiring of the headlights?

[I attached an image of the truck for the curious]




Thanks!

 

I haven't looked into the BCM for the 2022, but would it be possible to set it as if it had halogen headlights? The halogen lights are just a basic 3 wire setup and would be easier to modify to the new lights. The other thing that might work is something like a wiring harness Morimoto uses for their LED replacement headlights. They pull power directly from the under hood fuse panel and just use the stock headlight wiring for signals for relays. Someone like The Retrofit Source may have an idea or a harness that will pull off what you're trying to do.

 

I think Anzo had something mixed up in their response to you. My 2017 with the factory LED lights uses the top set for Low beam and the top and bottom set for high beam. I had to find the high beam signal wire to tie my light bar in so that it only comes on with the high beams. Someone else trying to do what I did a while back with a 2020+ truck had different headlight wiring than what I had and was having trouble even finding a high beam signal wire. So there are definitely differences in the wiring between 2017-2019 and the 2020+ trucks. Do the 2020+ trucks use both top and bottom for low and high beam and then adjust power output to make them brighter or dimmer?

 

Not sure if it makes a difference as I have no idea what part of the headlight system controls which lights, how many lights etc........17-19 LED equipped trucks had one headlight on for the low beams, the top light. The 17-19 halogen equipped trucks had all 4 lit up for low beams. 2020+ is when the LED's also started having all four lit for low beam.....I don't know if there is a physical part from a 17-19 LED truck, or a program change that could be used to make your truck function as a 17-19 would. Thought it might be worth mentioning anyway.

 

Not sure about your last question. The low beam is definitely on top in this headlight, though

. And to add some more information, the folks that built my truck put an LED bulb and system on the low beam. The bottom (high beam) is the H7 Halogen bulb [image attached]. It is connected to <something> but who knows what.

 

Does your truck have up-fitter switches? Wire the high beams into that if it does.

 

That is in the fallback plan. I have a couple of spare upfitter switches still. Though honestly, I would rather the switch be physically as close to the high beam as possible for my own sanity if I am going to go that route. I don't have a hood release cable anymore so I have a nice easy port through the firewall for a new switch too :]

 

This is correct. My 2021 high beam signal is not detectable under the hood when they're powered. At least I was not able to find it. The 2017 - 2020 signal wire is pretty easy to find in the headlamp wire harness. Can also confirm on my 2021 that high beams power all 4 lights (top and bottom).

 

I might need to put an oscope / signal analyzer on some wires and see if there is some sort of signaling going on over some of these wires. It can't be that complicated, in theory.

 

I would say go for it.

If I remember correctly, there are 16 pins on the harness. None of the pins showed any change in voltage switching from low to high beam. If you figured this out I'm sure other members would be grateful.

 

Thought I would give everyone little update on my research. Unfortunately, I didn't get to see the factory LED wiring setup, only what my upfitter did, so I think I am missing some pins and such that are probably wrapped up in the wiring harness and I haven't tinkered with it yet. Here are my latest thoughts on what is likely going on with F250 LED Headlights:

Internally power is supplied by a couple 12V supply that is "always on" when the lights are on. One constant 12V supply for both lights (two hot wires, one 12V supply for each "beam). These LED headlights have a microcontroller lthat likely talks directly to the BCM (maybe through a standardized protocol like SPI, maybe right on the CAN bus, who knows). It simply communicates directly with the lights to control what happens in terms of high/low beams. Just speculating, but probably by activating more LED lighting elements. I haven't torn a housing down to know for sure. The easiest way for me to figure this out would be to find a stock platinum with LED lights, throw in a shim harness, and analyze the signal. It doesn't work on magic! There is probably a low voltage (3.3V or whatever) line that communicates with the light microcontroller. All of this could be wildly wrong, too, so keep that in mind. I am just speculating based on the fact that both lights do for sure get a constant 12V supply. It ain't being controlled with magic and fairies. It could be something simpler like PWM or... who knows.

Anyway, this leads me to believe someone will have to reverse engineer whatever communication protocol is going on and build a "downfitter" harness that has at least some circuity in it to interpret these comms and power up a circuit on a relay or something in my situation. And since very few people are "downgrading" their lights, that ain't too likely to happen. But it might also be that aftermarket light makers would want this to provide alternative headlights eventually and they too will need to know the LED protocol, but I think it is far more common for people with halogen housings to ugprade to LED ones, which are much easier to upfit based on what I know. Anyhow, I think I have a more permanent, if not beautiful, solution.

It was suggested to take the dash apart and follow the wires from the steering wheel/stalk assemblies and use a piercing (needle) probe to find the wire that actually activates the high beams. It is just one wire that sends that signal. You can then tie that wire to a relay for a higher voltage 12V circuit and control the lights that way. It is low tech, but seems like it will work. So, that is probably what I am going to end up doing. This is moderately painful to do, but it could be worse.

 

Awesome update. This was my speculation as well. I haven't proved it, but it is one of the only plausible answers.

 

Quick question and not trying to be an intelligent donkey, but why is the builder/upfitter not doing this? For what I imagine you paid for this, they should be making this right for you.

 

Overall I am quite pleased with the workmanship and quality. I have off-roaded it and everything mechanical is solid and well done and the truck runs and drives great. Things could have gone better, though.

What follows is a moderately unhappy story.

I originally sent the truck to MegaRexx in Tuscon, who built virtually every other MegaRexx out there. Anyway, the owner sold the business and MegaRexx name to guy out in Wilmington. My truck was one of the first ones finished by the new owners in Wilmington. It did not go smoothly between the new owners and old owners, though it was originally intended to be a harmonious transition. This headlight issue was not brought to my attention until I took delivery of the truck and I didn't really think to check the headlights... cause you just assume they worked that out. I am mechanically and electronically inclined so I am handling it because they were not willing to figure it out. I would rather just do it myself or with local off road shops I trust at this point. I think I will ultimately ask the new owners to settle up with me as this is not the only issue I am resolving, some of which I am doing through my local Ford dealership I bought the truck at. It is almost all small stuff, but the attention to detail on some of this stuff just wasn't there. It is definitely not the way you would hope things would go, they got it 90% right and seem to have only missed on details... but, as you implied, when you spend this kind of coin you expect everything to be just right. The other list of issues is worthy of its own post. (Like, why they could not figure out the pre-collision / adaptive cruise radar calibration issues, despite allegedly hiring a Ford tech with proper VCM/Ford diagnostic software and F250 knowledge, here is a hint... the sensor has to be perfectly level, lol). They also fried the BCM and had to replace that, causing a 2-3 week delay on the build because it was throwing power train codes and such, but it was all in the BCM as far as I could tell. The new shop should have communicated these minor issues and done more to resolve them with me. They were also like 2-3 months behind schedule, I wanted it done.

Ultimately, I think this split and loss of institutional knowledge from the old MegaRexx team greatly contributed to a lot of my minor issues. I am a pretty understanding person and I just wanted the truck back. The remaining issues were all things I knew I could handle locally. The end.

 

You sound like a very patient and reasonable person, which they should appreciate. If they can't make it right for a person like you, god help them when the next customer is raising hell and threatening lawsuits.