HOW TO: Making the low beams stay on with the high beams - '99-'02 GM trucks

DV2000NJ

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Disclaimer:This is ONLY for '99-'02 trucks, and possibly SUVs. It will not work on '03+ trucks.

So do you have a '99-'02 truck, and hate that your low beams shut off when the high beams come on?

Well, you've come to the right place. This is commonly called the "4-high" mod, since you'll have all 4 bulbs on when the high beams are on.

Basically all is being done, is we're grounding the negative wire to the low beam bulb.

Take out the the headlight, and unplug both the high beam and low beam. Take the low beam plug, and locate the yellow wire. This is the wire that is not orange.
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Cut the yellow wire.
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Tape up the end in the wire loom so it won't get wet and other bad stuff.
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Strip the end of the yellow wire, and get some wire to extend it with. I twisted, soldered, and heat-shrinked mine.
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Next, you may have to wait for the pouring-ass rain to stop. I did.
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After the rain stops, get a connector like this:
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And solder it to the end of the wire you used to extend the yellow one.
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Now find a place on the body/chassis to bolt it to. I bolted mine on top of the little support bar that goes over the battery from the fender to the radiator support.
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One side done.
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Next, we can watch the MINT condition GMT400 big block dually owned by the old lady down the street drive by.
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Repeat on the other side. I bolted that side to the plate that sits under the air filter (or the stock air box if you don't have an open element CAI).
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Low beams.
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Lows and highs.
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That's pretty much it. :dunno:
 
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drperry

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Nice writeup on the quad beam mod :thumbs:

Now, eventually, when you change that bulb, you'll actually have 4 headlights :lol:

For the '98 + S-Series... Ground the yellow wire on the high beam, IIRC... Splice it in :lol:

I think that's another way of doing it with the GMT800s as well.
 

daddy

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Must have. :D
 

OldCracker29

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Sweet Dan. The pouring rain, and old lady drive by were awesome. :thumbs:

On a more serious note. Nice write up. :cheers:
 

Black02Silverado

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Sweet. I might just have to do that to the truck today while I'm busy doing all this other stuff to it. It sure will be nice having bright lights while in the mountains of Pa when I go home later next week to visit my parents. :)
 

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