Fog Lights
 

I installed some 4" fog lights that sit on top of my bumper today, they were bright as hell on the guys truck that I bought them from, and on my truck, there is light, but they are extremely dim. I had aftermarked fog lights in my bumper already, little 3" lights that sit on each side of the license plate. They are decently bright, but they don't project.

There is already a dash in my cab for those fogs, so I figured I would hook the new ones into the wiring for the old ones, that way the switch would run all 4. The ones that were already on the truck are still the same brightness, but the new ones aren't bright at all. I'm wondering if having all the lights off the same power would cause them to be dim.

I used some pretty thin gauge wire to wire them up, it was all I had. Would using thicker gauge wire effect the brightness of the lights?

I have heard of cases where thin gauge wire was a culprit of dim fog lights. You might want to use some heavier gauge wire.

How do you have them wire exactly. Are you pulling power through the switch itself? If you are I would HIGHLY recommend you wire the fog lights on a relay system that pulls power strait from the battery. I would also recommend no wire smaller than 14 gauge. I would personally use 12 gauge.

I just put a set of fog lights on my '89. I wired them into a relay mounted over by the battery. They came with a switch rated for the light, but know better.

Those 50w bulbs draw pretty big power, so if you wired them with 18ga wire, it's not going to work well(the wires will get warm).

Do what everyone else has suggested. Use large gauge wire and make sure the lights are run off a relay and that shood take car of any issues you are having.

The 3" fog lights that were already on the bumper were installed by the PO, I don't see a relay setup anywhere, so I'm pretty sure those are just wired through the switch. And the fogs I added on I just tied into the wiring that was already there.

I won't use the fogs for now, when I get some time in the next few weeks I will wire it all into a relay and all that good stuff. I was reading up on some diagrams and it really doesn't seem too hard.

Thanks for all the help guys.

Wattage divide by 13.8 volts = amps

example:
50w lights x 2 since there are 2 of them = 100w

100 divided by 13.8 = 7.24 amps

typical fog light wiring is about 18-20 feet

so you would need... a 12 ga wire

You want 12 because you should ONLY RUN 80% of a circuits capacity

Take your amps and go to this chart for the length of wire and what gauge
http://www.gtsparkplugs.com/WireSizeCalc.html
Also, make sure your switch is rated for the amps, if not you will need a relay

Thanks for the input Brad. Idk the amp rating on the switch as I didn't buy it, so I'm gonna use a relay just to be safe.

I had the exact same problem when I did mine I switch to 18ga we and the light are nice and bright!!

Here's how easy it is to do.
Mount the relay next to the battery, then hook up the wires.

http://www.classictruckshop.com/club...ch/foglite.jpg

the indicator light is optional.

18AWG? Damn, what did you have on there before, 22!?!?

Get you some 14AWG and I bet they'll be even brighter.

I got some 12g wire and I am going to try it without using a relay first, that way I don't have to rewire everything. I am going to wire the new fogs into the pre-existing fogs with the 12g wire and ground them independently from the other fogs instead of tying it into the ground for the old fogs.

If that doesn't work I will rewire everything with a relay, and probably add a new switch into the mix.

And the wire I used when I first wired in the new fogs is like 22g lol it was from a heated ice scraper my buddy had it was the only wire we could find. Hmm I guess I usually find out that I should do it right the first time but for some reason I love jerry rigging things and trying to make it work...

Actually you don't have to rewire much to add the relay. Take the wire going to the switch and cut it(up front somewhere) and use it to control the relay. Run the wire from the lights(that you cut) to the relay then add a power wire from the battery to the relay. Whatever you have the switch wired to for power is okay since it won't be doing much other then control the relay.

Basically you are only adding ONE wire(relay to battery). Your existing wiring is fine.

Wired in a relay, you were right Freightrain it wasn't much work at all. Also swapped in the 12ga wire, and ran a ground for each of the lights instead of tying them all together. The fog lights are a hell of a lot brighter now. All for 15 bucks in stuff. Thanks for all the help guys.