Anybody know where to grab a Hi Beam ground?

Oldfart said:

I just called BD back and asked more questions and now he says you could use the positive for a switch wire, but that it's not possible on a '20 because there IS NO high beam wire, it's internal. I'm so glad I already pulled the original fully installed harness out after I got his first advice when I received the high beam harness! Thanks to tech support @Baja Designs for making a bunch of needless work for me.

@FordTechOne do you know this one by any chance? Is there a high beam lead wire that can be used for a relay?

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Baja Designs said:

That harness is used with a traditional style headlight with three leads, low, high, and ground. On most automotive applications, power is switched between low and high with the headlight switch. But on newer vehicles such as a 2020 Ford Raptor, I believe they've changed that. You can confirm this with a multi-meter or test light probing the leads from the back of the headlight. What you're looking for is a lead that has power in the high beam, and no power in the low beam. That would be your high beam wire. But hopefully a FRF member can chime in on that and what they've incorporated. Most customers run our lights to the auxiliary switches on Raptors. If it's a switched ground design to go between low and high, that harness will not work. That relay needs switched power to trigger a closed circuit.

To answer your previous question, the red wire has 12v constant power and would be left capped like in the picture. The black is for the load (lights) and is tapped into switched power (ex. high beam circuit).

-Paul M.

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FordTechOne said:

The headlamps have 2 separate circuits coming from the BCM to provide power for the low and high beams in each headlamp, but neither can be used to power a relay. This is due to the fact that the BCM uses a Field Effect Transistor (FET) to power each lamp. The FET measures the current draw on the circuit; if current draw is out of range (short to ground, open, etc) it will disable the circuit output and the BCM will set a DTC. Therefore, if you install a relay in any of those circuits, FET will detect the additional current draw, power down the circuit, and a DTC will set in the BCM.

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FordTechOne said:

You are correct, power no longer runs through the headlamp switch on newer vehicles. Instead, the headlamp switch is simply used as an input to the Body Control Module (BCM); no current runs through the switch. This design was implemented on Ford vehicles in the mid-late 2000's, back when the BCM was referred to as a Smart Junction Box (SJB). The design is beneficial because the switches no longer generate heat due to current flow, and are no longer any high-current contacts to wear out within the switch.

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