Gmt900 Headlight Fog Light Mod.

[Mike74]

OK, this may be a repost, but I could not find it for the GMT900 trucks. I found 1 post in another forum for this, but the write up wasnt all that good and it took me awhile to figure it out. So, I decided to take better photos and try to do a better write up.

 

First off, this mod is not under the hood like previous models (I found alot of that). Second, go to Radio Shack and buy the Micromini Silicon Diode, 12v. I used P/N IN4001. I read that 1 thru 5 will work though. It comes with 2 in a pack for .97 (I just bought them today).

 

Under the dash on the drivers side, you will see an air vent. To the left of the air vent, you will see a gray plug. This is actually a stack of plugs, gray being the first, then pink, then a dark orange and then black, with more above that. The balck on (4th up) is the one you want. You can remove the vent or reach around it like I did and unplug the black plug and fish it down to you. It has a little push in on the side facing the firewall that you will push while you pull it out. Once you have done it, you need to find the Green wire with the white stripe and the peach wire with the white stripe. Once you locate these 2 wires, take your diode and stick it in the hole with the wires. The side of the diode with the stripe on it goes into the peach wire and the other side into the green wire. Once you get them in good, you can plug it back in. Now your highs and fogs will be on at the same time!

 

Here are the pics:

[Mike74]

2nd pic

[Mike74]

3rd pic

[jandersinc]

Will that also cause the fogs to come on with the low beams automatically? I'm more interested in that mod if you know how to do that.

[Mike74]

No, but I am sure I can figure it out. The peach wire is the high beams, so all you need to do is find out which wire is the low beam and put your diode in that hole instead of the peach and they will come on with the lows automatically. Same with the DRL's. Just find which wire that is and plug it in there. As long as the stripe side of the diode goes into which wire that runs the lights you are wanting, the fogs will come on automatically with them.

[Mike74]

Will that also cause the fogs to come on with the low beams automatically? I'm more interested in that mod if you know how to do that.

 

Ok, got it. Found this on another forum finally. Go from the 85 pin on the headlamp relay to the 85 pin on the fog relay. Now anytime the headlights are on the fogs automatically are on. Make sure the stripe side is facing the headlight relay.

[jdell]

Is this mod for the fogs to come on with DRL's? Will the fogs still go off with high beams? Can you give a better explaination of this and what material is needed? Thankss

[mjdxtreme]

Is this mod for the fogs to come on with DRL's? Will the fogs still go off with high beams? Can you give a better explaination of this and what material is needed? Thankss

 

 

Take a look at this thread it explains it all

 

http://www.gm-trucks.com/forums/index.php?...hl=my+fogs+work

[Mike74]

Is this mod for the fogs to come on with DRL's? Will the fogs still go off with high beams? Can you give a better explaination of this and what material is needed? Thankss

 

 

Take a look at this thread it explains it all

 

http://www.gm-trucks.com/forums/index.php?...hl=my+fogs+work

 

 

 

There ya.... I dont know why I could not find that early. I literally searched all morning for it. Anyways, jdell, to answer your question. If you do it the second way mjdxtreme's way, the fogs will be on anytime your headlights come on. If you do it the way I posted to begin with, you can still turn them on and off with low beama, but they will always be on with high beams. As for DRL's again, find out which wire and change the diode to it or get a sec diaode and put it in both. As for better explanation of materials, I listed exactly what was needed. In the pic from mj, he just added wire to the ends of the diode to make them longer and looks like he added heat shrink as well to protect the bare diode.

[FarmerDave]

The way I did it, fogs only come on when you turn them on. But come on automatically with the high beams.

[jdell]

Thanks for the info.

[Mike74]

The way I did it, fogs only come on when you turn them on. But come on automatically with the high beams.

 

That would be the way in the first post I did.

[Mike74]

Not to bring up an old thread, but wanted to let everyone know that this will work on 11's as well. I just did it to my 2011 Chevy 1500..

[uchi]

just did this on my 09 sierra, works like a charm, thanks

[TJay74]

Anyway to get the fogs to come on with the lights on a 2001 Silverado, I hate having to turn them on each time. Heck hate doing in my 2008 Corvette as well, stupid engineers.