4-HI Headlight mod 03+

[GB's 03]

Up date. Only problem I got is that the DRL's don't come on in the day light. I may mess around with it a little more. Twilight feature still works fine.

[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.

[StuckInTime]

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.

It sounds like you have the setup I am looking for. I really don't care about my DRL's being on, but I do want my fogs on with the low beams at all times, and if I turn the high beams on I would like everything else to stay on (fogs, low/high). Since you have an '03 GMC I would guess that if I did the same setup it should work. Can you tell me what part numbers you bought for the diodes? Thanks much. -TK

[GB's 03]

Diodes are IN4004. You can get the at radioshack in a two pac for like $.84. Where in Indiana are you located? Are you going to the 4x4 jamboree in Indy?

[Kenny C]

Originally Posted by StuckInTime

It sounds like you have the setup I am looking for. I really don't care about my DRL's being on, but I do want my fogs on with the low beams at all times, and if I turn the high beams on I would like everything else to stay on (fogs, low/high). Since you have an '03 GMC I would guess that if I did the same setup it should work. Can you tell me what part numbers you bought for the diodes? Thanks much. -TK

The instructions for what you want to do and the part numbers are all listed with photos in the first post. I know that you said your BCM part number is different, but other GMCs have done this mod either under the hood or dash using the same diodes with the same results. Hope it works out for you

[Kenny C]

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.

Thanks for the added info

[StuckInTime]

Originally Posted by GB's 03

Diodes are IN4004. You can get the at radioshack in a two pac for like $.84. Where in Indiana are you located? Are you going to the 4x4 jamboree in Indy?

I'm in South Bend, and I will definitely be at the Indy Jamboree. Thanks for the info on this, and thanks to all those who've posted on how to do this. I'm no wiz at electrical systems, but can usually follow directions (depending on the number of preceeding beers!). -TK

[GB's 03]

I will be at the jamboree on saterday only. I took off saterday so my little girl could ride in the monster truck. I have to work sunday. If I see your truck I'll stop in and say hi. If ya don't have the lights done I'll give you a hand. I'm only an hour south of south bend.

[StuckInTime]

Originally Posted by GB's 03

I will be at the jamboree on saterday only. I took off saterday so my little girl could ride in the monster truck. I have to work sunday. If I see your truck I'll stop in and say hi. If ya don't have the lights done I'll give you a hand. I'm only an hour south of south bend.

Thanks for the offer! Hopefully I will have this figured out before the Jamboree, but I have a lot of other work that needs done before then also. If you see my truck definitely stop by to say hi. You shouldn't be able to miss the group I'm with (South Bend Sod Busters Off the Road Club). We will have a banner, canopy, quite a few trucks, and this:

[jniolon]

I've been looking for this info for some time and a buddy on the shop-talk forum clued me into this site...

I've read all the info on the 4 bulb conversion and the wiring is no problem... my concern is heat.. I've got a 2003 tahoe and I'm concerned about the heat buildup running 4 bulbs and melting the plastic headlight housing, etc...

any problems encountered out there ?????

also... anyone know of a source of good hi watt driving lights that will fit in the two extra holes in the air dam next to the aux lights ????? somebody has got to make them... the holes are just begging for them

tia

John

[Kenny C]

Originally Posted by jniolon

I've been looking for this info for some time and a buddy on the shop-talk forum clued me into this site...

I've read all the info on the 4 bulb conversion and the wiring is no problem... my concern is heat.. I've got a 2003 tahoe and I'm concerned about the heat buildup running 4 bulbs and melting the plastic headlight housing, etc...

any problems encountered out there ?????

also... anyone know of a source of good hi watt driving lights that will fit in the two extra holes in the air dam next to the aux lights ????? somebody has got to make them... the holes are just begging for them

tia

John

I run silverstar bulbs, but hardly get the chance to run 4 hi for any great length of time. So, no I haven't had any trouble with melting the housings.

I have heard of melting the housings even when just running the low beams if you run the super hi watt bulbs.

As far as the other lights your wanting, you could propably find the info you want by using the search button on the top of the page. Sorry, wish I could be more help.

[ME_TOBSTER]

I just did this to my 04 crew cab Z71. it worked just fine and was simple as hell. 15 minutes and am done. How ever my BCM has a different number on it #15116066

[blue72camaro]

Does anyone know what pin parking lights are on the connector.

[Kenny C]

Originally Posted by blue72camaro

Does anyone know what pin parking lights are on the connector.

I looked for a schematics sheet and aparantly, I don't know what I am looking for or where to look. After a few HOURS I gave up. You might PM atomic and see where he got that drawing at:duuno:

[GB's 03]

Just do your parks in the fuse box under the hood. What are you trying to hook them to?

[blink182house]

ok i did it on my '03 GMC Sierra 1500 and it worked, 15 minutes max, lol more like 5! my buddy has a '00 silverado though and his only has 3 plugs instead of 5 on the box, with different colored wires and etc, does anyone have the diagram for that setup? please get back to us asap thanks!

[bettshunt]

KennyC,
I am new to this forum and have a few questions, since you sound like you have made several mod's on your truck! I have a 2002 1500HD, will the 4-HI headlight mod work on my truck?
Also I have installed factory fog lights (as many others have) and realized after the fact the BCM has to be reprogrammed. I would like to use the factory switch if possible, but local dealer wants $80 to reprogram it! Is there a way to wire these up an alternate/safe way? Thank You

[054.8silverado]

is there a way to have all the lights on when i hit the brights but i dont have factory fog lamps?

[Kenny C]

Originally Posted by bettshunt

KennyC,
I am new to this forum and have a few questions, since you sound like you have made several mod's on your truck! I have a 2002 1500HD, will the 4-HI headlight mod work on my truck?
Also I have installed factory fog lights (as many others have) and realized after the fact the BCM has to be reprogrammed. I would like to use the factory switch if possible, but local dealer wants $80 to reprogram it! Is there a way to wire these up an alternate/safe way? Thank You

Sorry about the response time, I have been out of town. As far as I know, doing this mod this way will not work on your truck. Here is a link to another write up that will work on your truck--->http://www.fullsizechevy.com/forums/showthread.php?t=113025

I would call a few different dealerships for price quotes on getting the BCM reprogrammed.

[Kenny C]

Originally Posted by 054.8silverado

is there a way to have all the lights on when i hit the brights but i dont have factory fog lamps?

If you use the diagram above...use only one diode and go from B4 to T1 and that will get you the 4 hi without the fogs.

If you decide to order a new valance with factory fogs from Mark, you may or may not have to have the BCM reprogrammed and then you could add the other diode to have the fogs come on with the lows.