DIY LMM All on Headlight + Fog Mod Using Diodes @ the BCM

[sailinstud420]

There was some confusion as to how to make the fogs stay on the with the high beams. Many have gone into the fusebox and put wires to the relays. I found another, and IMO better way. This way the dealer wont see it.

You need a Diode from radio shack, I used the 4004's, they come two in a pack and cost one dollar.

 

[sailinstud420]

The BCM is above the drivers feet, you need to remove the HVAC that blows on your feet to access it. There is a push pin the the outboard side that needs to be removed, then it just slides off and out of the way.

 

[sailinstud420]

Once you locate the BCM you need to remove the BLACK plug in. That is where the wires are for the fogs and the brights.

 

[sailinstud420]

Now that you have removed the black plug, you need to connect the two wires with the diode. The wires you need are Tan/White (high beams) and Green/White (fogs). The diode goes in the Tan/White with the "bottle cap" nearest to the high beam wire (tan/white), from there place the other end of the diode into the Green/white slot for the fogs.

This is the tricky part, it is tough to get the diode down inbetween the wire and the plastic, that needs to make contact down in there in order to work. I found it easiest to get it started by hand and then push the diode down into there using a set of needle nose pliers. It might take a couple try's to get it down in there well.

 

[sailinstud420]

That's all there is to it. Plug the black wire back into the BCM and try it out! If it doesn't work you either have the diode in backwards or you are not making a good connection... Take it apart and try it again.

Reconnect your plastic HVAC, put the floormats back in and you are finished.

 

[sailinstud420]

With this diode installed you can have all the configurations. Fogs on with no headlights, Fogs on with low beams, and fogs on with low & high beams. The only thing you cannot do is turn the Fogs off when the High beams are on.

I assume no responsibility for anything you MESS UP! I did this to my '04 LLY 2 yrs ago and haven't had a problem yet!

 

[Unit453]

Thanks so much for doing this..!!!

 

[Max Attitude]

Nice write-up Nick.

 

[Sgt.Badger]

Works ! Couldn't get it to work then a friend figured out I was actually pushing the diode in to far. and failing to get a good connection. Very neat... Thanks !

 

[seminole]

YYYYOOouuuu the man Finally thank you

 

[seminole]

It works !!!!!!!! Thanks again