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

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TheFuzz

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OK guys and gals, here we are. I read the original 4-hi mod that JK had over at TahoeForum, which utilized quite a bit of wiring and involved a SPDT relay. Well, I read on here that for us guys with 2000-2002 model year Tahoes/Yukons/Escalades, all you need to do is ground out the yellow wire that goes into the driver's side low beam.

How does this work? Well, in a simplified nutshell, the relay that controls the highs and lows basically kills the gound to the low beams whenever the high beams are switched on, thereby turning the lowbeams off while the highs are on. By adding a permanent ground to the yellow driver's side lowbeam wire, you have bypassed the relay's ability to switch off the low beams. This has no effect on your DRLs, fog lights, etc, and is a very easy modification to do. I'll walk you through it step by step.

First, open your hood and locate the driver's side headlight assembly. You will see the tops of two L-shaped pins sticking out of the top of the housing, shown here:

4hiMod001.jpg

To get them out, you simply pivot them toward the front of the truck...
4hiMod002.jpg

...and lift them completely out.
4hiMod003.jpg

Thats it - those two pins are all that holds the headlamp assembly in place. Be forewarned, they are not secured to the vehicle in any way, so once you pull them out, make sure you put them in a safe place. If you lose them, you're gonna be using duct tape to hold your headlight on until the dealership can replace them for you.

Anyway, at this point, unplug the wiring harness from the low beam and high beam bulbs, which disconnects the headlamp assembly from the harness. Set the headlamp aside (you've already got it loose, so why not just remove the thing and put it somewhere? Makes it much easier to work, and you're not stressing the wires by letting the housing hang from them while your trying to work).

Now that you have a nice open area to work with, locate the low-beam wires - there will be one orange and one yellow wire. It's the yellow wire we will be working with, shown here:
4hiMod004.jpg

Now, this is where people can use their own method to ground the wire out. Remember, we are NOT completely clipping this wire and grounding it - we are SPLICING a separate, additional wire INTO the existing wire to provide a constant ground. I used some 12ga wire (about 10-12 inches should be plenty), a 12ga wire tap, and a round butt connector for the ground connection:
4hiMod005.jpg

One I got everything tapped into the existing yellow wire, I grounded it to the diagonal brace right above the battery. For whatever reason, I spaced getting a picture of it...but there are a host of bolts you can use in and around the engine bay to get a good ground. If you need to use more wire, use more wire...but less is always best, IMO.

Here's another veiw:
4hiMod006.jpg

And another view with the headlight housing plugged back in:
4hiMod007.jpg

Make sure that your new ground wire isn't going to get in the way of your L-pins that hold the headlight on, and get 'er all put back together:
4hiMod008.jpg

When you're done, this is what you should have:
4hiMod009.jpg

Super easy, and inexpensive! If for whatever reason it's not working for you, make sure you have a good ground bolt selected, and that your wire splice/tap/whatever you used is tight and in good condition. Thats it, you're all done!

Pretty cool huh? Takes all of ten minutes. Enjoy!
 
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TheFuzz

TheFuzz

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:waytogo: thanks bro will try this asap... is it necessary to tap both headlights?

No problem! Nope, just the driver's side will suffice. As long as that relay is getting a constant gound, you're good to go. You can tap both if you wish, but it's not necessary for the mod to work.
 

jESse

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now we just need to figure out how to do a 6 high for the 00-02's. think this ground wire thing will work for the fogs too? anyone electrical smart enough to figure it out? lol
 

Mr45

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No problem! Nope, just the driver's side will suffice. As long as that relay is getting a constant gound, you're good to go. You can tap both if you wish, but it's not necessary for the mod to work.

Mine needed both sides grounded to work. But I cut the original yellow off, and capped it. Yellow from the bulbs now only goes to ground.
 
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TheFuzz

TheFuzz

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Mine needed both sides grounded to work. But I cut the original yellow off, and capped it. Yellow from the bulbs now only goes to ground.

Thats a good way of doing it, too. My method requires less wiring work though...and I'm lazy so thats what I prefer. :D

Thanks for sharing though. There are multiple ways to do this mod, this one just happened to be the easiest for me. :Handshake:

---------- Post added at 10:23 AM ---------- Previous post was at 10:21 AM ----------

now we just need to figure out how to do a 6 high for the 00-02's. think this ground wire thing will work for the fogs too? anyone electrical smart enough to figure it out? lol

I'm actually working on that one as we speak...if I can figure it out, I'll do an additional write up for the 6-hi mod (with pics of course :)).
 

BOSS

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Stickied...looks great, someone please post your results with this :)


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