auto headlights

[Smiththers]

i suppose it depends on the car, but i kept turning my fog lights on and off till i found the relay under the dash. from there i identified which wires did what. in my car i had two wires i had to make changes to. first one is the negative wire signal going to the relay, this wire is the one that comes from the fog light switch on the directional switch, and is interrupted when the high beams are turned on. to fix that from happening i soldered a wire directly from the fog light switch to the relay and isolated it with a diode in the direction that allows a negative signal to go to the relay. if you dont diode isolate the wire from the foglight switch, the foglights will get stuck on whenever there is 12v going to the relay. the other wire on the fog light relay i had to modify is the wire going to the relay that supplies 12v when ever the headlights are turned on. i cut the original wire and soldered to the 12v output wire from the parking light relay to fix that problem. this will totally depend on the lighting relay setup for your car, as ive only torn into mine and nothing else. i dont see why it would be wired differently, but just make sure you've got your logic probe or a digital multi meter with you when you start looking for wires. i like being able to run my fogs at any time, and i cant wait to delete the DRL's. i hope this gets you started in a good direction for this mod and if you or anyone else needs help, i will do what i can. i fully intend on getting to know my car's electrical system well.

 

[Stein]

Smithers, sounds like you know more about electricity than the average Joe. I wish I could go messing with my car's electronics and not break anything.

So fog lights are usually tied to the highbeams, while driving lights can be on whenever? Does the difference have to do with the aiming and preventing the blinding of oncoming drivers? Eventually I want to get some cheap driving or fog lights and I want to get things sorted out before I end up with the lights sitting in my room because I can't install them the way I want yet.

 

[Smiththers]

as far as i know, the fog/driving lights are suppoesd to turn off whenever the highbeams are on, and i think that's the rules of inspection but i could be wrong. i dont know how driving/fog lights are meant to be aimed though. As far as electronics go, i spend about 8 hours a day working on cars, 95% is electronic stuff. (its my job) The key to learning electronics is to read and read some more. The idea behind not breaking anything is a good one, but even i manage to kill something once in a blue moon. The best thing you can do if you are venturing into the unknown is to test every thing with a good logic probe or multimeter, solder all connections, and dont ever leave anything exposed. Its not going to be an over night thing, but you are young and will learn very fast.