4-HI Headlight mod 03+

[GB's 03]

I don't really know what happens. I never touch the switch. I just let it do its own thing.

[blackbike82]

This is the best mod ever. This Mr. Cheapskate just used elec tape instead of heat shrink, left the heat duct on unplugged dropped in diodes and plugged back in. After $1.94 for diodes, less than 2 minutes, up and running.

I had one of those kits from summit on my 90 1500 this is so much easier.

[sailinstud420]

okay this may be a repeat question, but I can't figure out what the heck you guys are talking about! I have a friend that we want his highs+lows+fogs+drl's on when he hits the high beam switch. Is this possible? I hear some of your diodes are cancelling things out?

Our thought is it will be so cool when people flash him for his lows (modded with high beam bulbs) then he can pull the stalk and give them some massive fire power! No one ever found a wiring schematic?

and btw, those diodes can be tricky to get jammed down in there, especially with heat shrink tubing on them, got any suggestions?

[sailinstud420]

bump.... I still wouldn't mind a little help.

[Kenny C]

Originally Posted by sailinstud420

bump.... I still wouldn't mind a little help.

Sounds like this is what your wanting

Originally Posted by GB's 03

I pulled all diodes and started over. Under the dash I went from B5 to T4 so the DRL's are on when the low beams are on. Then in the fuse box I went from #85 on the high beam relay to #85 on the low beam relay.(4-HI) Then from #85 on the fog realay to #85 on the low beam relay so the fogs are on when low beam are on. When you turn on the high beams every thing stays lit. Twilite still works and DRL's work like factory. Tonite some poor guy left his brites on to long and I thought he was going to wreck.

If you pull the relays in the fuse box under the hood, the pins on the relays should be numbered.

It sounds harder than it is...just take the chit apart and you will understand more of what's going of.

[sailinstud420]

can it be done without going in the fuse box, or is this the only way?

[Kenny C]

Originally Posted by sailinstud420

can it be done without going in the fuse box, or is this the only way?

I have mine done under the dash at the BCM, just like my first post states. But, my DRLs only come one during the day and go off at night just like they are supposed to.

I think that if you want the DRLs to always be on, then you have to use 2 diodes on the relays in the fuse box and 1 diode on the plug at the BCM.

[spyvie]

okay this may be a repeat question, but I can't figure out what the heck you guys are talking about! I have a friend that we want his highs+lows+fogs+drl's on when he hits the high beam switch. Is this possible? I hear some of your diodes are cancelling things out?

Yes it is possible. The diodes don't cancel out but each one causes a voltage drop of around .7V so more than 2 in cascade will probably not have the juice to kick the relay.

Our thought is it will be so cool when people flash him for his lows (modded with high beam bulbs) then he can pull the stalk and give them some massive fire power! No one ever found a wiring schematic?

Why do you think it's cool to purposefully blind people and provoke them to flash you just so you can show them how much brighter you can be? It has to get annoying, I get flashed enough with standard lows.

and btw, those diodes can be tricky to get jammed down in there, especially with heat shrink tubing on them, got any suggestions?

Yeah, leave about 1/4" bare. Fold the end in half back on itself so you have kind of a tight 1/8" U end. Then bend the end that is facing the insulator to the side a bit so that you have extra contact in two planes. Worked like a champ for me anyway.

[sailinstud420]

what pin at the bcm is are the drl's? I don't have fogs on my truck so the voltage drop shouldn't be an issue... we just did my friends truck tonight, we have his hi's + lows + fogs on and it is bright! Plus he has the adapters to run the high beam bulb in his lows and high beam bulbs in his fogs (9005's i believe).

I got to thinking I might try to pull the backward reflectors out of the low beam slots, is that possible? If I could ever find time to work on my truck I would try it, but there seems to be a wealth of info on this site.

One more thing, anyone ever managed to get some kind of brighter bulb in place of the reverse lights? I wouldn't mind being able to see what I am backing into a little better either.

As for blinding people, why not? Plus we live out in the country so it is pretty nice to light the road real good at night.

[GB's 03]

DRL's are the 4th pin over on the top row of the bcm. Green/black wire.

[sailinstud420]

thanks, one more question, what would happen if they two diodes do contact eachother (not insulated)? would it just blow fuses or would we have serious issues?

[GB's 03]

I have no idea, and I ain't going to try it to find out.

[spyvie]

As for blinding people, why not? Plus we live out in the country so it is pretty nice to light the road real good at night.

Umm, cause you could cause an accident. I live in the country too and realize the benefits of a well lit road and that's what the highs+whatever are for, however using brighter bulbs for the low beams for the purpose of being a nusciance/hazard on the road just doesn't seem all that "bright".

Not only that, michigan police WILL stop you for failure to dim lights. That can be an inconvience when you are unable to dim them.

[gotbags?]

i am gnna try this out

[gotbags?]

worked great easy to do also good forum

[badz24s]

Hey guys, I'm new here and have been spending a lot of time reading all the tech articles here. I just got my 07 classic sport crew last weekend.
I want to do this mod. I don't have foglamps. I want to have my drl's on with the lows; and lows w/drl's on with highs. Basically, 4 hi's plus drl's. All I would need to do is connect a diode from high to low, and from low to drl, right?
Doing this, i would put the stripe end of the diode in the high beam and connect it to the low beam wire. then put the stripe end of the other diode into the low wire and connect it to drl's. Does this sound right?

Thanks,
Stephen

[domestictuner]

is this possible on an 99-02 i know the 02 has a a box in the same place as the 03 but have yet to take the plug out and look at it...

it has to have similar relays and connections somewhere right?

it did work like a charm on the 05 suburban i did.

[spyvie]

My 99-05 Hayne's manual shows the same wiring diagrams for 2000+ so I would say just make sure the wires are the same colors.

[domestictuner]

Originally Posted by spyvie

My 99-05 Hayne's manual shows the same wiring diagrams for 2000+ so I would say just make sure the wires are the same colors.

thanks

[05Quadrasteer]

I did this mod to my 05 over the weekend. Did the fogs on with low beams and then everything on with highbeams.

The only problem I ran into was my BCM could not be pulled out. It was hitting on the dash, so worked gently and figured out how to remove the connector from the BCM with it still mounted in place.

Everything is working great. Thanks to all those who figured out the correct wire positions and parts required.

Have a nice day.

Bill