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Wiring LED Bar to High Beams

Josef

By Josef
in Modifications, Wheels & Tires

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Josef Enthusiast

Josef

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Posted

I am looking to wire my Baja Designs Lightbar to my high beams.  I know that its not legal to drive like this on the road so I plan to have a switch between the high beam wire and the relay to shut it off if needed.  I have seen that people have done this but I cant figure out how/where people are getting power from the high beams.  There are two high beam fuses in the box but they are tiny and I cant find an add a fuse solution.  I would prefer not to tap into the wiring but if thats the only option where are you all doing it?

 

The S8 light bar also as the amber driving light portion that I am likely going to delete because I dont want it to be powered on when the truck isnt powered on.  Beaming that I plan on having the high beams trigger the relay I dont think this is easily possible.  If anyone has any ideas there as well that would be great.  Thanks in advance for any advice.

jflan23 Enthusiast

jflan23

Posted
Posted

Ok, I did this with my two spot and my wide beam light install on my AT4. Keep in mind this is how I did it knowing I will be changing it around in the future. If you want to use a switch to toggle the lights on and off you’ll need two relays to do it right. If you want them always on with high beam you can get away with 1 relay.

Switch relay (relay 1)
High beam relay (relay 2)


Step 1- you need two SPST relays. 86 on both will be grounded, 30 on the switch relay (relay 1) will need to be fused directly from the battery at an amperage high enough for your light bar. Mine is 15 amps.


Step 2-switch relay (relay 1).First I ran a ‘zip’ wire (two wires bonded together) through the firewall and into the truck. These two connect to a regular toggle switch that I have floating around cause I didn’t want to drill a hole. If you have a lighted switch you will need a ground wire as well. 18 gauge is plenty for this. This switch allows me to turn the light bars on or off. (Only trips on with high beams with the 2nd relay). 12 volt into the switch is one of the wires, fused at 3 amps directly from the battery. The wire going out goes to 85 on the relay.

Step 3-switch relay out to high beam relay(relay2). 87 from relay 1 goes to 30 of relay 2. This basically sees the switch on trigger and allows it to activate the second relay which will use the high beam trigger.

Step 4- high beam relay (relay 2). I tapped into the high beam right at the harness going into the headlight. It was just easier for me. I metered and verified the correct wire and used a solder with heat shrink style “butt”connector to tap it. This is the signal wire to trip the high beam relay. It will go to 85 on the high beam relay.

Step 5- 87 on the high beam relay (relay 2) will
Be the 12 volt output that will power your light bar.

Using relays this way keeps your light bar from drawing too much amperage from the factory high beam wire so it doesn’t mess with the computer. The switch will allow the system to be on or off. Works nicely with the auto high beam as well if your truck is equipped.

  • Like 1
Josef Enthusiast

Josef

Posted
  • Author
Posted
7 minutes ago, jflan23 said:

Ok, I did this with my two spot and my wide beam light install on my AT4. Keep in mind this is how I did it knowing I will be changing it around in the future. If you want to use a switch to toggle the lights on and off you’ll need two relays to do it right. If you want them always on with high beam you can get away with 1 relay.

Switch relay (relay 1)
High beam relay (relay 2)


Step 1- you need two SPST relays. 86 on both will be grounded, 30 on the switch relay (relay 1) will need to be fused directly from the battery at an amperage high enough for your light bar. Mine is 15 amps.


Step 2-switch relay (relay 1).First I ran a ‘zip’ wire (two wires bonded together) through the firewall and into the truck. These two connect to a regular toggle switch that I have floating around cause I didn’t want to drill a hole. If you have a lighted switch you will need a ground wire as well. 18 gauge is plenty for this. This switch allows me to turn the light bars on or off. (Only trips on with high beams with the 2nd relay). 12 volt into the switch is one of the wires, fused at 3 amps directly from the battery. The wire going out goes to 85 on the relay.

Step 3-switch relay out to high beam relay(relay2). 87 from relay 1 goes to 30 of relay 2. This basically sees the switch on trigger and allows it to activate the second relay which will use the high beam trigger.

Step 4- high beam relay (relay 2). I tapped into the high beam right at the harness going into the headlight. It was just easier for me. I metered and verified the correct wire and used a solder with heat shrink style “butt”connector to tap it. This is the signal wire to trip the high beam relay. It will go to 85 on the high beam relay.

Step 5- 87 on the high beam relay (relay 2) will
Be the 12 volt output that will power your light bar.

Using relays this way keeps your light bar from drawing too much amperage from the factory high beam wire so it doesn’t mess with the computer. The switch will allow the system to be on or off. Works nicely with the auto high beam as well if your truck is equipped.

Wow that was quick and thorough.  Thanks a ton.  You dont happen to have an image of where you tapped into the high beam harness do you?  I am assuming the engine compartments and wiring are fairly close between the AT4 and Trailboss LT.

jflan23 Enthusiast

jflan23

Posted
Posted
Wow that was quick and thorough.  Thanks a ton.  You dont happen to have an image of where you tapped into the high beam harness do you?  I am assuming the engine compartments and wiring are fairly close between the AT4 and Trailboss LT.

I don’t have a photo, it’s wrapped in tape now lol. If I recall correctly I grabbed the harness right at the headlight. I believe the harness goes through a grommet before plugging into the headlight. Granted the gmc headlights are a bit different but I assume it’s somewhat close. Regardless there will be a high beam wire going into the headlight housing, you’ll have to verify which one first but it’ll be there.
JansterZ71 Enthusiast

JansterZ71

Posted
Posted
1 hour ago, jflan23 said:


I don’t have a photo, it’s wrapped in tape now lol. If I recall correctly I grabbed the harness right at the headlight. I believe the harness goes through a grommet before plugging into the headlight. Granted the gmc headlights are a bit different but I assume it’s somewhat close. Regardless there will be a high beam wire going into the headlight housing, you’ll have to verify which one first but it’ll be there.

Do you have a picture of the LED bar placement day and night?  I have an AT4 and ive been thinking about installing a bar as well.  Thanks

jflan23 Enthusiast

jflan23

Posted
Posted
Do you have a picture of the LED bar placement day and night?  I have an AT4 and ive been thinking about installing a bar as well.  Thanks

258daa4c9bf20037fe4bf91887890d60.jpg


I don’t have a night pic. I basically cut the plastic valence above the bumper in two pieces and put the lights in the middle. Two are spots the center is wide angle.
JansterZ71 Enthusiast

JansterZ71

Posted
Posted
1 hour ago, jflan23 said:


258daa4c9bf20037fe4bf91887890d60.jpg


I don’t have a night pic. I basically cut the plastic valence above the bumper in two pieces and put the lights in the middle. Two are spots the center is wide angle.

Wow, that looks really good.  I'm too scared to go cutting to my bumpers, but that looks like its from the factory!

  • 1 year later...
Josef Enthusiast

Josef

Posted
  • Author
Posted

So I finally got around to doing this.  Thank you Jflan for getting me 90% of the way there.  Ended up setting up a relay so that light bar is only powered when the truck is on.  I then set up a relay so that my high beams trigger the light bar to come on.  Because youre not supposed to drive on road with light bars I also added a switch on this relay so that I can have my high beams without the light bar on.

 

Both relays are triggered from the fuse box inside the engine compartment.  I just used simple add a fuses for this.  High beams fuse for the light bar relay and the parking lights for the whole system relay.  I slotted the cover so that I can get the wires out of the box. The fuse box covers are cheap if I want to return it to stock.

 

I would prefer to find a fuse in there that is acc power on and not necessarily tied to my parking lights.  I would like to keep this so that it can be easily returned to OEM without tapping into wires (I would prefer to use these add-a-fuses).  Issue is that during the daylight with my headlights in auto the parking lights toggle off which kills the whole system.

 

Does anyone know a fuse in this box that its acc power on?

RedLT Enthusiast

RedLT

Posted
Posted
On 12/28/2021 at 7:15 PM, Josef said:

So I finally got around to doing this.  Thank you Jflan for getting me 90% of the way there.  Ended up setting up a relay so that light bar is only powered when the truck is on.  I then set up a relay so that my high beams trigger the light bar to come on.  Because youre not supposed to drive on road with light bars I also added a switch on this relay so that I can have my high beams without the light bar on.

 

Both relays are triggered from the fuse box inside the engine compartment.  I just used simple add a fuses for this.  High beams fuse for the light bar relay and the parking lights for the whole system relay.  I slotted the cover so that I can get the wires out of the box. The fuse box covers are cheap if I want to return it to stock.

 

I would prefer to find a fuse in there that is acc power on and not necessarily tied to my parking lights.  I would like to keep this so that it can be easily returned to OEM without tapping into wires (I would prefer to use these add-a-fuses).  Issue is that during the daylight with my headlights in auto the parking lights toggle off which kills the whole system.

 

Does anyone know a fuse in this box that its acc power on?

Headlight fuse #4. It receives power when the truck is turned on but does not turn on the headlight (headlight function is controlled elsewhere).

  • 2 weeks later...
Josef Enthusiast

Josef

Posted
  • Author
Posted (edited)

Using fuse #4 I get an error when I put my left turn signal on when the headlights are off during the day.  It’s strange because that fuse is labeled right headlamp and I don’t get the error when I have the right turn signal on. 
 

edit:  nevermind I believe that this error is unrelated to the light bar install. 

Edited by Josef
Update
Josef Enthusiast

Josef

Posted
  • Author
Posted

Just to circle back on this.  I believe the #4 fuse should work just fine for keyed acc power.  The issue that I had was related to a loose ground wire on a canopy install.

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