I want to upgrade my stock hadlight wiring harness on my 90 v6 pickup but don't know ich to buy. I have done some searching and found several, autobulbdepot(seems to be out of bussness), suvlight, and some universal apc ones on ebay. It seems that everyone on here uses the suvlight one, but I am not sure wich model to order.
Also it looked like on the sulivght harness you only use one of the stock female end plugs(if I am even looking at the right one for my truck)?

And if it makes any differance I have Hella Vision Plus Halogen Headlights

 

anyone?

 

I have heard good things about Painless wiring, but sadly, I know nothing of your application.

 

Actually, it might be better to do what I did. When I decided to upgrade my headlight harness, I just made my own with 10-gauge wire, two relays and a fused power source. It's really not that hard to make your own DIY harness. I also incorporated the fused high/low beam circuits into the stock fuse box. I just used two vacant fuse slots under the cover to put the wires/fuses in for a clean look. I currently have the Hella H4's with the stock supplied bulbs for now.

With the huge 10-gauge wires, the 65w/55w stock Hella H4 bulbs are pretty darn bright the way it is. It's a BIG difference compared to the old X-tra visions/stock harness I had in there before.

Toyota uses a switched ground system for their headlight circuits. At least in the pre-Taco years. What you're basically doing is using the stock factory harness on your truck as the "trigger" leads to the relays while the relays handle the power from the battery to the headlight bulbs.

By using the factory harness as the "trigger" leads, you don't have to butcher anything. You can make it so you can switch back and forth from either harness in a couple of seconds. Also, if you ever sell the truck you can easily take the DIY harness with you.