I just installed 8000k HID headlights and fog lights in my truck. I ordered 2 relay harnesses with them but I didn't install them; I just plugged the HID's into the stock wiring. Should I have also put the relay harnesses in? and what do the relays even do? I haven't been active on this site in awhile but I will update my photos and page soon!

Thanks,
~Austin

 

the purpose of a relay is so you can run a heavier gauge wire to an accessory, where the original wiring is not heavy enough. instead, it just uses the original wiring as a TRIGGER for the heavier gauge wire, the relay has a little electromagnetic switch thing inside it that flips when it detects current in the "signal" wire.

I don't know if your HIDs will draw more current than stock lights, depends on the kit but I'm just guess it doesn't. I'm really not sure but that IS what a relay is for in any circuit

 

The relay harness does a couple of things.

It isn't so much a wire gauge issue, considering HID's are typically 30-35w draw compared to 55-65w halogen draw. It's more so a reliability issue the relay harness is solving.


Generally, fogs don't need a relay harness. I always suggest it for headlights though. Since they're on two different circuits from the factory(you have a left and a right side fuse).

 

Thanks for all the information, it all seems clearer to me now. I think I will put the relay in today on the headlights and update my page as well with more recent pics!

 

Dont bother with the relay unless you have issues with them firing and in some cases that still wont solve it. The relays were really designed for vehicles equipped with drl's

 

I decided to leave out the relay harness. Here's a daytime pic of my HID's...I will have nighttime ones later tonight.

 

Looks good.