The SUPER EASY 4-Hi mod for 00-02 vehicles

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ArcticYukon

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None. It's not like the old day when the power ran through the switch. Ours all run through relays in the underhood fuse panel.

Exactly this. You can run as many lights as you want using the factory headlight switch as long as you're running them off relays.

Learned that trick when I owned my Jeep. Installed relays for the the high and low beam headlight circuits on my XJ along with upgrading the alternator, battery, and the battery and alt cables. People couldn't believe I was running factory sealed beams on it when it was all said and done.
 

BeenChevy

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Screenshot_20180903-194318~2.png Get yourself a pre-configured relay harness online. They're about ~$6 and you can simply plug and play between your stock headlamp harnesses and batt.
 
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jeff69

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Did the mod as in post one.... now drivers high beam, the side where i tapped the low beam, is out. Checked all fuses, HL and DRL relay, but no power to the socket on the high beam that was just working before modding.

02 Tahoe
 
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Rocket Man

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Did the mod as in post one.... now drivers high beam, the side where i tapped the low beam, is out. Checked all fuses, HL and DRL relay, but no power to the socket on the high beam that was just working before modding.

02 Tahoe
Well the mod had nothing to do with the high beam if you did it right. All you were doing was adding a constant ground to the negative wire on the low beam instead of a switched ground on it. So either you have a bad high beam socket or a broken wire on the high beam somewhere. Or you did the mod wrong.
 

BeenChevy

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Is this an HID or halogen hi-beam setup? you swapped with the correct relay? If you're not getting signal to the relay, ya gotta work back to the switch.
 

RAMurphy

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Back in 2004, I installed a kit that provided me the 4-Hi mod. It was actually was a bit complicated. The kit included the wiring, a fuse, a waterproof relay and the required hardware. Recently, the relay went bad and instead of paying for and installing another relay - I ripped out the old kit and utilized this very simple and well documented Mod. I even used the yellow wire from the old kit to complete this install. Took 5 minutes and cost me nothing. Works great.
 

Mudsport96

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Super late to the thread, but I read everyone splicing and tapping the yellow wire... on a friends 02 I just separated the drivers side connector and pulled the grommet out, slide a 2nd wire through it and reassembled with a dab of silicone. Then grounded that wire per usual. Works great and no splicing, granted it took 10 minutes but it's all water tight vs a tap splice, and looks near factory.
 

Rocket Man

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Super late to the thread, but I read everyone splicing and tapping the yellow wire... on a friends 02 I just separated the drivers side connector and pulled the grommet out, slide a 2nd wire through it and reassembled with a dab of silicone. Then grounded that wire per usual. Works great and no splicing, granted it took 10 minutes but it's all water tight vs a tap splice, and looks near factory.
I just cut the wire, soldered and heat shrank it. How are you connecting the new ground wire to the yellow wire? You left that part out. Solder I assume?
 

BeenChevy

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Super late to the thread, but I read everyone splicing and tapping the yellow wire... on a friends 02 I just separated the drivers side connector and pulled the grommet out, slide a 2nd wire through it and reassembled with a dab of silicone. Then grounded that wire per usual. Works great and no splicing, granted it took 10 minutes but it's all water tight vs a tap splice, and looks near factory.

Yep, I like your method. Ran into a couple issues with water and corrosion and wished I had taken a little extra time. I've since soldered and heat shrunk a new headlight pigtail and wiring harness to both lights with a relay for HID's that's holding up well.
 

Mudsport96

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I just cut the wire, soldered and heat shrank it. How are you connecting the new ground wire to the yellow wire? You left that part out. Solder I assume?
Sorry, no solder. Just released the pin from the connector and slid it and the new wire back into the plug at the same time. No room for solder, but its such a tight fit I dont see it as necessary. Its water tight and still a better connection than a tap splice
 

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