GEN 2 Opinions/Input on wiring lights into the high beams.

smurfslayer · Nov 13, 2020

The downside to overdoing it is you lose your circuit. It may not blow the fuse, but it may set a soft code ( not CEL ) or outside indicators. Maybe FordPass gets notified but I’m not sure. This could happen when and where you can fix it, but most likely it will scram when you’re in the middle of Nowhere, BFE and about dusk, so you will have the maximum difficulty effecting a repair. If that happens, you’ll have to clear the code to reactivate the lights. That would be a chore.

Szabo Mihaly · Nov 13, 2020

The Aux switches should have a relay. If so, it will be triggered all the time if Aux is on and the second relay triggered by hi beam is of. Is not possible to connect somehow the signal from the hi beam to the Aux relay? Like that i can have the light on if aux and hi beam is on.

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FordTechOne · Nov 13, 2020

KeithV said:
I've been considering this too and I've heard the warnings, but also people saying they've done it and haven't had problems. I'm a total idiot compared to a lot of you guys on here about the newer electronics and BCMs. The one thing that confuses me a little bit is the quote FordTechOne put from BBAS:

“Never drive additional electrical load directly from the Body Control Module (BCM) output. The BCM output must drive an auxiliary relay coil only. If you try to drive an aftermarket electrical load directly, the BCM will likely disable the output and you may have to replace the BCM.”

To me, that appears to be saying you shouldn't drive lights directly from the BCM, but you should use a relay coil. If they didn't say the relay coil part, and just said don't drive additional electrical load from the BCM, then I can understand not attaching anything into that circuit. But when it states about driving an auxiliary relay coil only, it seems like that is acceptable. I'm confused LOL

Also, it was stated that first it would throw a DTC, and then shut down the circuit if it continued. So does that mean your lights would stop working and you would know there was a problem before it completely bricked the BCM?

Sorry for my ignorance. The much tighter electrical tolerances on these newer vehicles certainly aren't something to be screwed around with. I will always take the safe road, I'm just confused by some of the wording and descriptions.

When upfitters modify trucks, one of the most common modifications is lighting. They’ll remove the factory lights and then install various aftermarket lights in place of the original. The circuit is then overloaded, which damages the BCM.

The message is instructing them to use a relay in the place of the original component (tail lamp, for example) and then use that relay to power the aftermarket lighting. The relay effectively takes the place of the original component, so in most cases it will function without the BCM setting a DTC.

The BCM will shut the lights down a number of times and set corresponding DTCs before it sets the code of death, so yes it typically wouldn’t be bricked if you only overloaded it once.

Brent13 · Nov 13, 2020

My Baja design light bar is wired to my high beams using a relay off the wiring harness to the headlights. Power coming from the battery with inline fuse. The factory headlight acts as a switch to turn on and off the light bar. Take it to a professional and it can be wired to have no impact to the factory lighting.

KeithV · Nov 13, 2020

FordTechOne said:
When upfitters modify trucks, one of the most common modifications is lighting. They’ll remove the factory lights and then install various aftermarket lights in place of the original. The circuit is then overloaded, which damages the BCM.

The message is instructing them to use a relay in the place of the original component (tail lamp, for example) and then use that relay to power the aftermarket lighting. The relay effectively takes the place of the original component, so in most cases it will function without the BCM setting a DTC.

The BCM will shut the lights down a number of times and set corresponding DTCs before it sets the code of death, so yes it typically wouldn’t be bricked if you only overloaded it once.

Okay, gotcha. Makes more sense to me now.

Is there any difference in finding a way to run a relay off of the high beam switch from the steering wheel stalk before it reaches the BCM?

FordTechOne · Nov 13, 2020

KeithV said:
Okay, gotcha. Makes more sense to me now.

Is there any difference in finding a way to run a relay off of the high beam switch from the steering wheel stalk before it reaches the BCM?

The high beam switch is integral with the multifunction switch, which connects directly to the Steering Column Control Module (SCCM); there are no accessible circuits. The SCCM networks the inputs from the switch to the BCM over the CAN bus.

Oldfart · Nov 13, 2020

Brent13 said:
My Baja design light bar is wired to my high beams using a relay off the wiring harness to the headlights. Power coming from the battery with inline fuse. The factory headlight acts as a switch to turn on and off the light bar. Take it to a professional and it can be wired to have no impact to the factory lighting.

What year are you talking about? Where is this wire that your professional tapped into? It's not like there are wires running into the back of the light.

Szabo Mihaly · Nov 14, 2020

Anyone knows the location of the Aux switch relays?

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Kmandoske · Nov 26, 2020

i have had my relay panel tied into my BCM for more than 2 years. The reverse triggers relays for the GJ lights and two other lights. My high beams are tied into realys that trigger all my forward facing lights. I use them all the time, I have not had one issue with my BCM. A relay draws a tiny bit of power from the BCM circuit. Just enough to hold the contacts closed.

Szabo Mihaly · Dec 9, 2020

Someone give me this micro relay. He say the coil power consumption is very low, i should not have problems. It is 360 mW (i have no idea about this number) Next days i will connect my baja design trough the high beam and aux switch.

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GEN 2 Opinions/Input on wiring lights into the high beams.

smurfslayer

Be vewwy, vewwy quiet. We’re hunting sasquatch77

Szabo Mihaly

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FordTechOne

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Brent13

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KeithV

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FordTechOne

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Oldfart

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Szabo Mihaly

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Kmandoske

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Szabo Mihaly

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