Is it possible to have the high beam head lights and the fog lights on at the same time on a 2003 GMC 2500HD D/A? I have replaced the fog lights with high output driving lights (100W EACH).

Yes, there is a way to have all lights on at the same time or other variations. It requires only some diodes from Radio Shack for about $1.50 some wire and shrink tube. Check out this thread:

http://www.dieselplace.com/forum/showthread.php?t=12804&highlight=Diode

As for the 100W bulbs in the fogs, be careful! I did the same thing in my 2000 and it melted the housing! These were the rectangular lights and may be different now, but just food for thought. They may are be rated high enough for the temp. of the 100 watt bulbs. I lucked out and the dealer replaced the entire lights under warranty.

I need the fog lights and the high beams to work independently of each other. IE: be able to turn on the high beams without the fog lights comming on, and be able to turn on the fog lights with the low beams.

I replaced the entire housing assembly, so I do not have to worry about the housing melting.

Sorry, I did not realize you still wanted them to work independently as well as together. I would think that there is a way to do that, unfortunately, I am not familiar with it. Someone with a greater knowledge of the electrical system would have to chime in.

Busboy - Where did you get new fog light housings? I would like to get brighter bulbs too, but I need the round style for the '05.

Thanks.

Mine are a 5" housing on the 2003. I found them on E-bay for about $50.00/pair. They are not a name that I recognized, but they work well just the same.

you could hook a 2 way switch into the BCM ground control, wire one side of the switch to ground and then tap into the wire at the BCM. The dk grn/wht one on the left side of the schematic


http://service.gm.com/engif/000/000/863/863586.gif

Sorry about the size, it wouldnt save the resize