headlights and fog lights

Discussion in 'Chevy Tahoe Forum (GMC Yukon, Cadillac Escalade)' started by rockrash, Oct 24, 2008.

  1. rockrash

    rockrash New Member

    Im sure this has been asked before but I searched and couldnt find what I was looking for. I want to hook up the fog lights so they come on with the headlights. Whats the best way to do this??
  2. Springthing

    Springthing Epic Member 5+ Years 1000 Posts

    I would just go ahead and tap into the wire that goes into the headlights right now. What I would do, and I'm sure you'll have others answering with their ideas, is:

    Run Hot (+) wire from the battery to an automotive relay on the input side. Run that out to the hot wires of the fog lights.

    Place an in-line fuse near the battery on the hot wire.

    Run the wire from nearest ground to the ground terminal of the relay.

    Set the ground on both fog lights to the closest area on the frame. Small metal screws and drillbit should let you place those without having to extend the ground wires of the fog lights.

    Now, to turn the relay on and off....

    Find the hot wire to the low beams of your headlights. It should be listed in the manual, or you can just simply test the wires at the headlights.

    Tap into either headlight wire and run it to the (+) side of the relay.

    Ground the other side and you should be done.

    When you turn on the headlights, power will be supplied to the relay and trip it closed. That will allow power from the battery source (through the in-line fuse) through the relay and to the fog lights.

    Just the way I'd do it!

    You'd need.. lights, in-line fuse holder ($3 or so), relay (another $3 or so), a little extra wire and some female terminal connectors. Everything else you should have in your garage!

    The diagram below is NOT mine. Linked from a site. I will host this image in the near future so as not so use that site's bandwidth. Here's how the wiring would work...

    30: wire from the (+) battery
    87: wire to the fog lights
    86: wire from the headlight
    85: wire to ground to trigger relay

    Last edited: Oct 24, 2008
    1 person likes this.
  3. yatch07

    yatch07 New Member

  4. dwill3015

    dwill3015 Epic Member 5+ Years ROTM Winner 1000 Posts

    Nice work Steven!
  5. Springthing

    Springthing Epic Member 5+ Years 1000 Posts

    Thanks! ... was a while ago!
  6. rockrash

    rockrash New Member

    Thanks for the info guys, thats just what I was looking for.
  7. csmac2004

    csmac2004 Member

    Sorry to play Devil's advocate, but why? I think fog lights look cool, but dang they're annoying for the rest on the road when they're not needed! Nowadays, these fog lights are basically another, if not brighter, set of headlights. When I'm in my truck, not as big of a deal. But when driving my Cavalier to/from work, I must say I HATE trucks driving around with their fog lights on! One of my pet peeves, but maybe that's just me...
  8. Springthing

    Springthing Epic Member 5+ Years 1000 Posts

    Fog lights have a different light pattern. The lights generally offer a wider range of view and let you see further beyond both corners out the front of your vehicle. They shouldn't bother other drivers in the least if they are installed properly. Fog lights are (should be) mounted low and are a relatively flat beam. They are designed to minimize glare in foggy conditions and thus are designed to offer a horizontal light as opposed to just lighting everything brightly. This also is the reason why some of the fog lights are yellow. The yellow lights are supposed to cut down on the glare from the lights reflecting off the fog and (again, 'supposedly') are made to cut through the white fog a little better.
    Last edited: Dec 12, 2008
  9. csmac2004

    csmac2004 Member

    I do understand what they do, but they are annoying. These fog lights on new trucks are extremely bright, and in my opinion a hazard, to others on the road. And these are the lights installed straight from the factory. So, although I do understand what you're saying about what purpose they do serve, having driven both trucks and cars, I know that the majority of trucks out there with fog lights on cause major issues for other drivers. You don't have to agree with me, but all I'm saying is consider the price others pay for your lights. At the least, if I have my fog lights on, other than when its actually foggy, I will turn them off when a vehicle approaches knowing what its like on the other end. That's all I'm saying. Therefore, I would recommend against hard-wiring them to the headlights as this will obviously remove the ability to extend such a courtesy to others on the road.
  10. jetcruiser

    jetcruiser New Member

    4 6 hi

    don't know if you did this yet, but two diodes from radio shack and about 20 min will do it too. drop me a line if you want the link.

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