Originally Posted by d_smith84

I searched and read various threads here and elsewhere about hooking a light bar up so you can use the dimmer switch to turn the light bar on and off and I still don’t know if it can be done. One persons says use a relay, someone else says you can’t use the light module to control anything else, and others say they are going to do it but never post back the results.

I have a 2019 f350 super duty with the quad lights, NO upfitter switches, which I can work around, and I would like to add a 40-42” led light bar in the grill. I assume I would either have to use a three way switch, or two separate switches, so I can either have it always on or I can control it with the dimmer switch, off with low beam, on with high beam.

So my question is; can this be done, without damaging some module, and if so does anyone know how? I will state ahead of time I am not very knowledgeable regarding electrical stuff especially when it comes or resistors and diodes. Thanks Dan

Originally Posted by 2020STX250

I'm wondering if you have led headlights if a solid state 12v relay would be a better choice than a traditional electro mechanical relay.

https://www.amazon.com/dp/B07RTW33Z2...ing=UTF8&psc=1

Originally Posted by Pugga

A diode is like a one way valve for electricity. You use them so you don’t unintentionally backfeed the circuit you just tapped into. It’s not necessary, in my opinion, but can’t hurt. You wire it in line with the wire you tap off the headlight circuit.

all I meant about the LED vs halogen is i’m not sure if the base truck wiring is more finicky with the LED headlight setup vs. halogen. In the scenario I wrote up, you’re only pulling an extremely tiny amount of power to trigger a relay. You should absolutely not use the leadlight circuit to actually power something else. That long light bar draws some decent amps. The individual LEDs don’t draw a lot but there’s a lot of them.

on a side note, wiring a long light bar like that to your high beams can make your high beams ineffective. Many of those longer bars are combo, flood on the outside and driving pattern in the middle. The flood pattern dumps a ton of light immediately in front of the vehicle, causing your eyes to focus there, rather than off in the distance like you want when you have your high beams on. That’s why your fog lights turn off when you put on your high beams. I ran a 32” combo bar for a bit but swapped them for Rigid hyperspot cubes. Very focused beam, long throw, very effective to compliment the high beams.

Originally Posted by Crotchety Ford truck only

Those "Rigid" lights are the berries huh........

Originally Posted by Pugga

I did this on my last ‘19 with halogen lights and will be doing it again with the new one (also a ‘19). I tapped off of the high beam wire at the headlight, ran that wire into the cab to a switch, from the switch to a relay. The relay should receive the wire from the switch as the signal wire and the power should come fused directly from the battery. That way, with the switch on, the light bar will cycle on and off with the high beams. With the switch off, your regular high beams work as they should but the light bar will stay off. I put the switch in my glove box so, when I go for inspection, the lights are there but they won’t cycle with the high beams and they won’t be able to turn the light bar on.

with LEDs, it could be a much different animal but I had no issues with this setup on my truck with halogens.