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2002 chevy trailblazer_lt
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Discussion Starter · #1 ·
So as most on here know, its no secret that getting the Quad Headlight function is extremely simple. I recently did the Lancematic DRL Killer with the Relay and it works great, no more DRLS and i have Quad Headlights, everything works like a dream

But heres the trick, when you click the stalk into the HighBeam Position yes the Highs and Lows both stay on together as they should, but the foglights turn off even though the lows remain on.

The Fogs are controlled Via the BCM, that little button on your dash isnt even remotely connected to your foglights, all that button does is send a signal to your BCM which commands it to turn on your foglights

Since the foglights are BCM controlled, just like the Highs and Lows are BCM Controlled, im assuming it has its own wiring etc going in / coming out of the BCM. Has anyone found a way to spice in / Rig up a way to make the Foglights stay on along with the Lowbeams when you are in quad headlight mode?

Ide assume its just another wire or two needed to splice into just like what was done with the low beams to get them to stay on when the highs are commanded?
 

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2003 chevy trailblazer_lt
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i did mine a little different to get them to stay on.. i left everything alone and added a switch for the highs to come on.. they still work normally with the stalk but ifi want them on with all other lights the switch by passes the bcm and everything and leaves everything including the fogs on.. i would imagine the same could be done with the fogs.. but since i went another way i never really looked into it..

 

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i did mine a little different to get them to stay on.. i left everything alone and added a switch for the highs to come on.. they still work normally with the stalk but ifi want them on with all other lights the switch by passes the bcm and everything and leaves everything including the fogs on.. i would imagine the same could be done with the fogs.. but since i went another way i never really looked into it..
How did you do the wiring for the overhead lights?
 

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Discussion Starter · #6 ·

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2002 gmc envoy_slt
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i think doing that method would affect foglight operation when im not using my highbeams though and want the foglights to run independently from anything else
Well, like I said, it worked for me. You can still turn on the fogs independently (alone). I actually have them hooked up to my lows and not my highs. I then have the same setup connecting my highs and lows.
 

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Discussion Starter · #8 · (Edited)
Well, like I said, it worked for me.
So your foglights turn on when you click the switch, even during the day when no high or lowbeams are in operation? it didnt affect anything negatively?

What are the wire colors that you spliced into for the relay?

From what it looks like the Low Beam wire is Solid Yellow in the wire loom? Anyone know the color of the Foglight Wire, you dont cut any wires you simply splice into them with wire taps correct?

From what it looks like you just get the relay, connect it to a 12V constant power source, a ground, and then connect the lowbeam wire to the switched power on the relay, and then connect the foglight connection to the output 12V of the relay, correct? This way when the lows turn on it will switch the relay to on and send power to the foglights
 

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So your foglights turn on when you click the switch, even during the day when no high or lowbeams are in operation? it didnt affect anything negatively?

What are the wire colors that you spliced into for the relay?

From what it looks like the Low Beam wire is Solid Yellow in the wire loom? Anyone know the color of the Foglight Wire, you dont cut any wires you simply splice into them with wire taps correct?

From what it looks like you just get the relay, connect it to a 12V constant power source, a ground, and then connect the lowbeam wire to the switched power on the relay, and then connect the foglight connection to the output 12V of the relay, correct? This way when the lows turn on it will switch the relay to on and send power to the foglights
Yes, correct to all. I did that twice (one for fogs+lowbeam and one for lowbeam+highbeam). I'm going to redo all of it though once I get some HID bulbs for my PIAA lamps. I want to make it a cleaner install because of all the wires currently all over the place under my hood.
 

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Discussion Starter · #11 ·
what color is the foglight wire im suppose to tap into underhood? The Lowbeam wire is Yellow, what color is the foglight one
 

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2 relays, 2 fuses, 1 switch... rather standard wiring... switch to relay..



and thanks bubster... i gotta redo some of the lites this weekend for MORA
No, up under the headliner and thru the roof, or what. My mistake on the way I worded the question.
 

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Discussion Starter · #15 ·
Thanks, i just did it and it works like i charm, now my Highs / Lows and Fogs all stay on at the same time just as i wanted
 
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