I was wiring up my fog lights to my cowl yesterday. wire up my hots and my grounds go to do a quick trial test, First ihave no lights. then shortly after i have smoke billowing out from my hood. What did i do wrong? the wire from the battery to the switch was burning up. the wire from the switch to the lights was fine. it wasnt burning up or even warm. Im so lost any help please.

 

do you have inline fuses on the power wires

 

Was it an illuminated switch? If so, you might have put the earth connection on the wrong terminal.

Rob

 

No it does not have inline fuses.

Yes it is a illuminated switch but its not grounded. I ran it like this for almost a month before i changed the location of my fogs and it was fine. Im not sure if i should try again and ground the switch and get a different gauge wire or what.

 

inline fuses are a must! and you should have a relay....


All of my lights run off fused relays and 12ga wiring.

Something grounded out with your power wire.


Run 12v power to the relay, then use the same gauge wire from the relay to the lights. And run the same sized wire for your ground off of the relay and the same size wire for your ground at the light.

Your switch only needs to run 18ga as it does not have much power running thru it. And it needs to be grounded.

The bottom terminal on your switch needs to be grounded, the middle terminal needs to run to the relay and the top terminal on the switch needs to run to a 12v source, whether you tap into your fogs, a constant power or whatever.

 

its true you have to have fuses or ur just gunna have problems with it. use 20amp or better

 

very well put, I couldn't agree more. If you do a search for fog light wiring you should hit some threads that contain a picture wiring diagram with details on the relay setup. That's by far the best way to prevent fires though....ALWAYS USE CIRCUIT PROTECTION DEVICES! Aka fuses.

 

quick noob question. What does the relay do? It seems like it just requires more wire that i dont need if i already have a inline fuse? quick explanation would be nice thanks.

 

basically the relay is an auxillary switch that carries the load instead of your main switch, the main switch then just activates the coil in the relay very little load that way. thats the K.I.S.S version of what a relay does

 

exactly! the relay only needs a couple hundred milliamps to activate. The switch gives that couple hundred milliamps to activate your lights and you do not have ANY major 12v power going thru your switch. It is a MUCH safer way to wire.


a simple way to put it,

your high current power goes thru the relay and your low current power goes thru the switch making it safer for occupants inside the vehicle.