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

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Rollin Thunder

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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


yes-7.jpg



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!!!


yes2-9.jpg



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.
yes3-5.jpg




IF you would like to continue to the 6 high mod ( and I know you do:brsh1:) 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.
yes4-5.jpg






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.


yes5-2.jpg


yes6-1.jpg






This should be your result with teh 4 high mod.


yes7-1.jpg






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


yes8-1.jpg
 
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Sepiroth

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Whoa thos pics show some detail, lol.

BTW, this is a great write up FOR SOMEBODY WHO HAS AN 03-06, lol.

Guess us pre 03 have to suck it up and deal lol.
 

jgiguere17

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not true

if you want a brighter light, find a pair of 9005 bulbs and inside where the prongs are where you plug it in, there are 2 raised plastic pieces, with a razor blade, cut them of so they are smooth. Now you have a high beam in the low beam and way better output, I did this for my commuter car a long time ago and it is great driving at night
 

Sepiroth

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Yes that is true however, since the 9005 bulbs typically are not coated, won't they cause a rather broad lighting spectrum? Uless you have your headlights adjusted. But who can really do that right, lol?
 

Rollin Thunder

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Yes that is true however, since the 9005 bulbs typically are not coated, won't they cause a rather broad lighting spectrum? Uless you have your headlights adjusted. But who can really do that right, lol?


Well I tried that as well. But the beam was all over. Since its not dipped. The lowbeam reflector throws it all over the place. Actully giving me less light ahead of me and more light in peoples faces.
 

jordankreutzer

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Does anyone know how to do a 6 high mod on the 00-02 trucks? Im guessing its not as simple, but non the less, it would still be something nice to have.
 

Rollin Thunder

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Does anyone know how to do a 6 high mod on the 00-02 trucks? Im guessing its not as simple, but non the less, it would still be something nice to have.

I will have to do some checking, I think after some research the fuse box may be the same and it may work on ANY NBS, but dont hold me to that, maybe i can find an 02 or somthing and check it to see. All I know is its NICE AND BRIGHT.


O yea, dont worry. The corvette gets the garage, I just had the silverado in there cause I had the heater on and it was nice and warm in the garage, LOL when I took those pics it was only 40 degrees out side and I froze my azz off, Usually were about 65-75 this time of year. :skep:
 

burbanman03

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wow i can see the light

RT thank you so much. the under dash thing was going to work for me either i did this in like two mins. it took longer to get the high beam relay back in with the diodes in there but man it works great
 

tribalbreak

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just did this mod to the denali and its pretty sweet... of course i did the 6 high mod haha... great write up rt... are there any harmful effects of this? strain on the electrical system? the be honest i dont know to much about diodes and jumping relays, so i just did it because it worked haha...
 

Rollin Thunder

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just did this mod to the denali and its pretty sweet... of course i did the 6 high mod haha... great write up rt... are there any harmful effects of this? strain on the electrical system? the be honest i dont know to much about diodes and jumping relays, so i just did it because it worked haha...

All the diode does is tell the relay to stay on. It does not take power from your low beams to run the highs. I had it set up like this on my 06 yukon for over a year with no issues.
 

Jesters.

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Thanks for the write-up! I will be making a visit to Radio Shack tomorrow then going to start on this!
 

Yang1815

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Just did mine last night. They didn't have the 3 amp ones in stock so I used 2.5 amp and it works too. A pack of 3 for $1.99! Would there be any problems though? Thanks for the write-up!
 

jgiguere17

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ok, what if you dont want to always run a 4 high. I will have to show my output pictures of a 9005 bulb that I use instead of a 9006. I have aimed it properly to aim straight down the middle and it looks nice. Just food for thought.
 
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