Fog light help


Old 11-02-05, 06:38 AM
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Fog light help

I bought a 94 Cherokee Country that was obviously somebody's project that they gave up on.

They ran one line for the fog lights (green) that goes from the lights to the interior of the cabin (They did it cheaply between the fender and frame and through the door). Then there is an apparent power line (red) in the cabin that is not hot but the fuse for it is pulled.

My question is what else I need to complete this circuit. Is it just a switch? There does not appear to be a ground on this line so I think something is missing.
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Old 11-02-05, 07:34 AM
Join Date: Apr 2005
Posts: 242
Sounds like your missing a switch.
Why don't you pull all that out and just run the hot and ground wire from the low beam straight to the fog light.
Splice the wire into the low beam wire behind the headlight.
When the low beams are on the fog light will be on. When high beam is on fog light will be off.
Old 11-02-05, 08:04 AM
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Thanks! Can I put the switch in between so I would have the option of turing the fog lights on?
Old 11-02-05, 10:25 AM
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I see only one issue with running an additional switch, with the exception of possible feedback to the low beam filament of the headlight, causing both your low beam and high beam to try to operate at the same time. Best way to prevent that is to insert a diode inline between the low beam line and the fog lights, but before the secondary switch, and this will need to be done on both sides of the low beam circut. The purpose of a diode is mainly as a protection circut for just that type of thing, and there is a type used in many high voltage applications known as, "Protection Diodes", just for that reason. They used to be readily available at Radio Shack, but they have gotten so far away from where they started years ago with the amatuer hobbist, that they hardly carry anything like that anymore. If you have a local TV repair shop nearby, they might possibly be able to sell you what you need, and they aren't that expensive.
Old 11-02-05, 10:37 AM
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WHOAA!!!!!! Way out of my range. If they powered it from the fuse panel and I have the line for the switch, why can't I just complete the set up and mount a switch somewhere?
Old 11-02-05, 06:52 PM
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You have it right. Just run it as a seperate circuit - fuse block to switch to lights. To answer the final portion of your original question, The body of the car is the ground. If you check the fog lights, you should find a wire or metal strip that goes from one side of the socket to the metal fog light housing, This, of course, is attached to the bumper or some other metal on the car, completing the circuit.
Old 11-03-05, 05:17 AM
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So it would be
red power from fuse box ->switch -> green line to light

After making sure that the lights are grounded to the truck.

Old 11-03-05, 05:39 AM
Join Date: Nov 2001
Location: North Texas
Posts: 2,345

Or you can install a relay like it should have to begin with.You will still need a switch to activate the relay but you can use smaller wire since all the amps will go thru the relay and not the switch or wires going to it.
Old 11-03-05, 05:46 AM
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fog lites

I would suggest that you install a relay in the circuit,,,, If you make the low beam wire your switch terminal , an powered the relay straight off the battery / alt. circuit it will make your lits probaly -30- 40 percent brighter, even if you install these newer blue style lites you dont get full effect ,, if you hook a voltmeter up to your headlite your probaly only going to get 11 to 12 volts maybe, hooking up the relay as stated above gives you full charging voltage of 13.5 to 14.5 volts , if you would like to make a quick check to see the diff --- , just run a wire from the battery postive to the back of the head lite low beam an start the car an turn on lites , an see how much brighter the one head lite is over the other , you will be very impressed at the results, ( just remember to remove the test wire after your done !!!!!!! PLEASE ) But yea its much simpler to just hook it up the route your going. if you like the relay idea I can give you full directions on how to wire one up its really very simple ,,,,,,,,,,,,,JIM
Old 11-03-05, 06:44 AM
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Thank you all for the wisdom. I experiment with many things on my rig because I don't really know squat. But I won't test my limited knowledge with the electric or the brakes. Ram, please go ahead and send to [email protected]

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