Fog Lights + High beams:

Mighty HD · March 28, 2004

To keep the fogs on with the high beams, cant you just wire the foglight hotwire (at the switch) to the headlight control switch.

I did this with my car, as well as a friends truck.

We found the wire that turned hot and stayed hot when the headlamps came on, when you switch the high beams on, the switch had no power, BUT in theroy with the 2500, if you keep power to the switch, it will keep the foglights on?

Right or wrong?

I will do the high/low beam mod soon, I'll just ground the yellow wire @ the drivers side headlight like I did on the old ZR2.

The factory fogs arent but 17? watts, but it's just for looks until I replace them with some good aftermarkets.

BlackSilver · March 29, 2004

Why would you want fog lamps with high beams?

Kinda defeats the whole notion, with all that bounceback. Usually I find fog lamps work best without any other lamps at all.

Mighty HD · March 29, 2004

To be honest for looks.

I will more than likely end up putting an aftermarket set in and wiring them with a relay into the factory harness, but I dont want them shutting off when I have the high beams on.

the extra light is always helpful when I'm down a DARK road with absolutely nothing on either side of me.

lrymal · March 29, 2004

For "helper" lights on dark rural roads, I'd want some auxillary lights up higher than the fog lamps, about where the bowtie is, just slight lower.

Your factory fog lamps, when used as fog lamps, are about the "best" I have ever used from an OEM design. It gets foggy here a BUNCH--- I mean a carve-it-with-a-knife fog and the fog lamps give a wide beam spread and keep the aim low. No bounce back at all. And they work. Nothing bounces back in your eyes.

Just to sum it up, I really think helper driving lamps would be too low where those fog lamps currently are. The lowness will be apparent when you are going up and down hilly rural roads during a dark night.

But, just my opinion.....

JimWilson · March 29, 2004

I can relate to why you want to do it.

Up where I live it can get pretty dark -- there's a lot of rural area's around here still. Some of those unlit back roads are quite difficult to safely navigate without some nice lighting (take a look at my sig and you'll see how I feel about the topic ). Toss in the Bambi's running about and you have a strong need to see everything.

Fog lights, by design, throw the light directly in front of, and to the sides, of the truck. That's VERY beneficial for dark, twisty roads. The high beams throw their light far down the road, which is good for long open stretches, but not so good for tight, two lane roads. Combining them both has some merits, for sure.

My setup has been wired so I can put the fogs on any time I want them. I also have the headlight wiring harness done in a manner that the lows stay on when the highs go on too. That combination of 6 lights, all with different patterns, means that there isn't a dark road in America that I can't light up like a football stadium.

That's all good...

builderpaul · March 29, 2004

I can relate to why you want to do it.

Up where I live it can get pretty dark -- there's a lot of rural area's around here still. Some of those unlit back roads are quite difficult to safely navigate without some nice lighting (take a look at my sig and you'll see how I feel about the topic ). Toss in the Bambi's running about and you have a strong need to see everything.

Fog lights, by design, throw the light directly in front of, and to the sides, of the truck. That's VERY beneficial for dark, twisty roads. The high beams throw their light far down the road, which is good for long open stretches, but not so good for tight, two lane roads. Combining them both has some merits, for sure.

My setup has been wired so I can put the fogs on any time I want them. I also have the headlight wiring harness done in a manner that the lows stay on when the highs go on too. That combination of 6 lights, all with different patterns, means that there isn't a dark road in America that I can't light up like a football stadium.

That's all good...

I have been trying, in vain, to find an interesting article on this subject. Not to start an argument but just to offer a different view. This study concludes that using fogs with headlights actually decreases the distance, in front of the vehicle, that you can see. It has lots of statistics and research data. The main point is that the retina, in your eye, decreses in size, due to the amount of light right in front of you. This limits the amount of light you see fron farther away. So highbeam for higher speeds are safer. Than highbeams with fogs.

You may think it is good to see the sides of the road close to you but it really does no good, at speed, because what ever you are seeing you could not stop for anyway.

CMNTMXR81 · March 29, 2004

Why would you want fog lamps with high beams?

Kinda defeats the whole notion, with all that bounceback. Usually I find fog lamps work best without any other lamps at all.

Because he like I want MAXIMUM lighting power when needed. I have my fog lights (well, they’re actually driving lights because they’re WHITE, not amber), on at all times at night or in darker conditions. Not just fog or inclement weather. On a dark road, I want maximum candlepower.

But to answer your question, I have not explored wiring the ‘driving’ lights to stay on with the highs. Everything is run through your PCM, so you’d have to jump a wire somewhere between the high beam switch and the realy before the PCM.

I have found though, that if you flip your highs on, release the lever, then pull it back again and hold it, it’ll keep your high and low beams on all at once. Unfortunately your driving lights do not come back on.

lrymal · March 29, 2004

I have not explored wiring the ‘driving’ lights to stay on with the highs. Everything is run through your PCM, so you’d have to jump a wire somewhere between the high beam switch and the realy before the PCM.

Dig around the site through the search engine and you'll find an ample amount of messages explaining how to hook the high and low beams up. One method is via a diode hookup, the other is through a relay.

Getting back to installing driving lamps where the fog lamps are, if you are in a hilly area, the driving lamps will be too close to the ground. You need them mounted higher. If you are in a flat area, then it won't matter.

Personally, I feel you are going to get light bounce back into your eyes if you drive in the fog at night, with all those lights, and not have real splash-down fog lamps providing the primary illumination source.

CMNTMXR81 · March 29, 2004

That wasn't an issue, I know it can be done and there are kits out there for it. I did it on a few other of my trucks. I just don't feel like messing with it on this one. Especially when I can simply hold the lever back.

Mighty HD · March 30, 2004

What a hot topic...whew...

All I want to do is get the fog lights to stay on with the high beams.

That's all.

I did this in my 98 grand am after playing wtih lots of wires, I finally figured it out and told everyone & their brother...

If you can find the foglight relay, you might be able to ground it to the headlight relay and trick it....

I'm sure it's different now...... BUT I'd still like it to be done.

I did the low/high's on in my ZR2 and it was ok...not as good as the highs/fogs though...

JimWilson · March 30, 2004

This study concludes that using fogs with headlights actually decreases the distance, in front of the vehicle, that you can see. It has lots of statistics and research data. The main point is that the retina, in your eye, decreses in size, due to the amount of light right in front of you. This limits the amount of light you see fron farther away. So highbeam for higher speeds are safer. Than highbeams with fogs.
You may think it is good to see the sides of the road close to you but it really does no good, at speed, because what ever you are seeing you could not stop for anyway.

I've heard, and read, similar information -- and logically it makes sense -- but in the real world, for me anyway, it doesn't work that way. I find that the fogs make it far easier for me to drive in the dark, and provide me with significantly less eye strain then not using them.

Mighty HD · March 31, 2004

after thinking of this..

And after speaking with another member of the board who attempted to do the same thing with the parking light / fog light switch hotwire deal...

I have thought of this:

My grand am had the same issue when I wanted the highs/fogs on. I jumped a relay and it's been fine for 2 years now.

The BCM controlled the foglights just as these do.

How about these two options:

the wire that goes OUT of the bcm to turn on the fog lights, hook that to the parking lights to achieve the on/off at all times

OR

http://www.n-body.net/tech/techdisplay.php...0','500

These arent my instructions but it gives an idea what I did.

Firetiger(MN) · March 31, 2004

I did it this way using the wires on the BCM so I didn't have to disassemble the underhood electrical center:

Keep in mind this is on a 2003 GMC - other years may be different, even 2003 chevrolet may be differant although I would think it would be the same. For all lights on with high beams:

The bcm is under the steering column, I had to remove the dash panel to get to it. There are 3 larger 24 or so pin connectors on it. The one I am referring to is the 24 pin on the left side.

This connector has 2 rows of 12 pins, one above the other. There are pin numbers associated with them but they were hard to read so I'll explain it like this:

Top row: 1 2 3 4 5 6 7 8 9 10 11 12 -we'll call T

Bottom row: 1 2 3 4 5 6 7 8 9 10 11 12 -we'll call B

T1 is black-white and is High beam control- tap into this and run to a spst (2 terminal) switch, if you are going to use a switch to disable this mod. On the other side of the switch solder 3 diodes with the band ends towards the switch. I used 1n4005 diodes. Now for each of the other ends of the diodes you will solder a short length of wire on and tap into these leads as follows:

T4- is green black and is DRL control

B4- is pink and is low beam control

B5- green white and is fog lamp control

When you're done make sure to insulate each of these ends of the diodes and wires from each other and everything else. Start the truck,turn the headlights on if it's not dark, and with you're new switch off everything should work as before, or as normal. Turn the switch on and with you're high low beam lever in the low position you're low beams and fog lamps should work as normal. Flip to high beam and everything should come on. All we're really doing here is operating the relays under the hood that turn these lamps on normally. There should be no problem with power as they are still getting power the factory way. My only concern is the grounds on the headlamps, I'm hoping they don't run too warm running both lamps at once, and I don't know if both lamps are grounded together or if they have individual grounds. I may have to upgrade the grounds if they give trouble. Hope this is somewhat understandable!

Further note- if you are testing with the ignition switch off the DRLs will not come on at all, that's why I said start you're truck in the testing. If you don't want to install a switch to bypass this mod just connect the band ends of the diodes directly to the T1 black white wire.

JimWilson · April 1, 2004

I have my fog lights (well, they’re actually driving lights because they’re WHITE, not amber)

The color of the light doesn't dictate the style -- driving or fog -- it's the pattern that does. While I have never seen anything other then a white driving light, the vast majority of foglights are not amber, they're white too.

lrymal · April 1, 2004

I have my fog lights (well, they’re actually driving lights because they’re WHITE, not amber)

The color of the light doesn't dictate the style -- driving or fog -- it's the pattern that does. While I have never seen anything other then a white driving light, the vast majority of foglights are not amber, they're white too.

The only piece to add to this is that a bluish/whitish light in fog, reflecting even a little bit back into the eyes is far more irritating to the eyes than an amber or yellowish light. In some costal countries, amber lo beams are required to cut through the perpetual haze at night. I used to live in West Africa and was amazed at all the "white lights" when I returned to the States.