hi i have an 05 gmc sierra 1500 and i noticed that if i have my factory foglights on and switch to high beams that the foglights turn off and i believe that is factory built in to my truck and i was wondering what i can do to be able to keep my fog lights on with my high beams?

 

they make a kit that a friend of mine has on his truck its a chip of some sort that makes the lights turn at the same time. i will try to find out what the name is of the kit and let you no.

 

Its just a relay you add on. Real simple.

 

thank you so much for everyones respones can anyone tell me the name of the chip or relay and what not thank you so much guys

 

Here ya go friend... http://www.streetsideauto.com/produc...ampaign=Become

Now I know its cheaper somewhere else. Heck you can even just buy a 30 amp relay at the parts store and do it urself.

 

Also some guys will look under the big electrical box under the hood and find the yellow wire and just ground it. That is the same thing.

 

I am also interested in having my foglights on with the parking lights, low beams, and high beams. When you say "ground the yellow wire", what exactly does that mean? Can you provide a little more detail please? THANKS!

 

In the earlier GMT800 trucks (99-2002?), it's a very easy mod. I'm not sure about 2004 and up; I think they changed some of the logic in the high beam light controls and added a second relay (one for the low beams, one for the high).

In any case, I highly recomend this for anyone that drives rural roads at night; it makes a huge difference. The jist of it is that when you switch on the high beams, the regular low beam lights are switched off. The high beams effectively illuminate anything further down the road, but the addition of the low beams really fills in the area closer to the front of the truck.

The high and low beams are in seperate housings, so heat generated by the bulbs really isn't an issue. As for the wiring, it's more than adequate. Each 55 watt bulb draws just a hair over 4 amps at 13.6 volts. You can carry that with a 23 gage wire safely, the 18 gage wire used can carry 4 times that.

On the pre-2003 trucks, the low and high beams lights are controlled by a single relay which gets it's signal from the Body Control Module. For some reason (probably having to do with the automatic light control or the DRLS) the relay is on the ground side of the circuit; in other words, the relay switches the headlight ground in and out to control the lights. The supply side of the circuit is always energized (at least when the lights are on) so all you need to do is provide another path to ground for the low beam lights. Some people have tapped into the harness at the bulb to do this, others have tapped the wiring under the relay board in the electrical distribution box on the driver's fender under the hood. Either method works essentially the same way, it's just a matter of where you tap the wires. On the bottom of the relay/fuse board there are 4 big connectors. The connector under the headlight relay has a yellow wire at position D5. This wire is the ground for the low beam lights (you can check continuity to the low beam bulb connector to be sure) Tap that wire to ground and you're all set.

In 2003 the logic was changed and they added another relay, afterwhich the BCM switches the hot side of the low beams in and out and a seperate relay switches the high beams in and out.

 

Ruffneck:
Let me throw this at you.

I did a little poking around with a DC voltmeter. I have a little understanding of automotive wiring. I do however get quite confused when I start dealing with switched ground.

It seems that the fog light switch provides the ground to the fog relay. This, along with the constant 12v positive that is present at the relay, closes the relay, illuminating the fog lights. My thinking is that if I provide a constant ground to the relay, then the fogs will not turn off. I am assuming if I could provide the constant ground to the fog switch, then the fogs would be on with low, high, parking lights. I am not quite sure how to determine the proper wire at the fog switch to ground.

 

i haven't been on here in while but last year i wanted to do the same thing. i found something on here that you can use a one way electrode and go from certain relay post to another one in the under the hood fuse box. i think if you search for it on here you might be able to find it or under ls1truck.com i believe had a good diagram. it's really simple. i did it but it would pull alot of amps, enough to move my battery meter on my gauge cluster. good luck on finding it