How to do the 4 or 6 high mod on an 03-06 full size truck for $3.00

Rollin Thunder said:

OK. Here is a right up with lots a pics on how to do the 4 or 6 high mod. I always do the 6 high cause the more lights the better and it only take an extra 2 min or so. I did this to my 03 silverado, but the fuse box is the same on an 03-06 silverado, sierra, tahoe, suburban, yukon, yukon xl and so on. So it does not matter. I did the same exact thing in the same exact places on my 06 yukon and had them on for more than a year with no trouble, would still have them If I had not traded it. OK. THe hardest part is makeing sure the diode touches some metel on the relay. We will start out with just the 4 hi mode. Some people say you can put a diode under your dash board, I tried this, im a big guy at 6'2 and it was hard for me to get in to position here, then you gotta worry about removeing the PCM thing and all that crap. This is just much easier for me.


Ok first. Open your hood.

Then find your fuse box.


open the fuse box. Find the two relays that say HdLP-high and Hdlp- low. high one is all by it self all the way to the left towards the hood of the truck. Low is second from the bottom closest to the driver fender. RIght below the low is the fog. Usually the fog relay is black while the rest are grey.

On to pics.


First remove the LOWBEAM relay. This may need plyers, I damaged mine but they still work fine (knock on wood). Put it in the RIGHT REAR socket, it wont fit in, just make sure the metel on the diode is touching the metel on the relay. Keep the grey band pointed towards the highbeam headlamp or yourhighs will be on when ever your low beams are on, if you find this, just simply reverce the diode.... sorry my first 2 pics are bad, the rest are much clearer, but you get the idea

THen put the lowbeam relay back on. were done with this one enless you did not make sure metel was touching metel here. KEEP IN MINE THE DIODE METEL SHOULD ONLY TOUCH THE RIGHT REAR CORNER DIODE PEG!!! OR NOM 85 ON YOUR FUSE BOX MAP!!!

Then pull out your highbeam relay. an repeat the above step... IF you only want the 4 high mod. Just put the relay back. The DIODE end must be in the RIGHT REAR of the highbeam relay as well.

IF you would like to continue to the 6 high mod ( and I know you do) Then follow these extra steps.





Remove the fog relay. Put the diode in the TOP LEFT of the fog relay. MAKE SURE THE GREY BAND IS TOWARD THE HIGH BEAM RELAY!!!! install your second diode. IF you got the radio shack ones they come in 2 packs. 3 amp 50volt resistor diodes. Re install the fog relay again making damn sure metel is touching metel and only touching that one relay peg.

Then this gets kinda tricky, but after a few beers you calm down and get it done. get both diodes to touch the same RIGHT REAR peg of the highbeam relay. Then just jam in the highbeam relay, make sure both diodes are snug.

This should be your result with teh 4 high mod.

THIS SHOULD BE YOUR RESULT WITH THE 6 HIGH MOD!!!

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Rollin Thunder said:

3 amp 50 volt diode is perfect. Also to do the DRL mod, Just find the DRL relay and repeat.

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vatahoelt said:

is there a way to wire it, so that the other lights are controlled by a switch when the highs come on? i'm sure someone has probably run their system this way.

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OmarR said:

Meaning....when you have your high beams on, you want to be able to alternate between 4 HIGH amd regular HIGH mode?

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DenaliAK said:

So, do the 4-high only. Then manually push the fog button when you want them on, too. Lots of cars automatically do the 4-high for high beams (Chevy/GMC is a little backward about this, actually), so I don't think you'd be bending any rules. Just leave your fogs off for inspection.

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Rollin Thunder said:

on 07 up it already does. But Im in va to and a cop isnt going to be able to tell all 6 are on since the low and high are so close together. Plus you turn your highbeams off anyway when close enough for someone to be able to tell.

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vatahoelt said:

yeah, but during inspection the inspector is going to look for the high beams to come on and the low beams to go off.

i'm pretty sure if i do the relay route with the 4 or 6 way high mod, then i could wire in a switch.

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vatahoelt said:

yeah, but during inspection the inspector is going to look for the high beams to come on and the low beams to go off.

i'm pretty sure if i do the relay route with the 4 or 6 way high mod, then i could wire in a switch.

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Rollin Thunder said:

Go do a buddy in the inspection world if you can. My guy just slaps a sticker on and says see ya next year.

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vatahoelt said:

i'll do this and then you can have your buddy send me up a new sticker when i need it.

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