Okay, I just recently did the H4 conversion on my truck, and ran into problems I couldn't find a solution to on here so I figured I would give a shot at a how to myself to maybe answer some questions others may have.
First a parts list:
I used a set of H4 high temp pigtails from Autozone brand was doorman, cost me like $12 for the 2 only sold in package of two.
some form of wire connectors(butt, quick splice, bullet, spades, etc...)
H4 bulb recommended but can test with just the HIDs
Okay first off you cut off you original h4666 plug on the DRIVER'S side. There will be 2 brown wires(low beams), 2 green wires(high beams), and one blue wire(ground). You will need to see which of the brown wires jump over to the passenger side.
Strip the ends of the brown wires and the blue wire. Twist the ends of the pigtail ground(black in my case) with the blue wire(ground). Then take the wire from the pigtail for the low beams(red in my case) and twist it with one of the browns. You can either just test with your HID kit that is already wired up or get an H4 bulb which should have came with your headlights if you're doing 4x6.
Turn on the lights, if you hear the relay kick on(if doing HID test) and no lights, wrong brown wire. If the H4 bulb doesn't kick on, wrong brown wire. If this is the case just switch to the other brown wire, and it should work just fine.
Once you have figured which wires belong together, use the splices of your choice to connect them permanently, I chose bullet connectors in case I need to disconnect them some day.
Also you need to disable your daytime lights, which if you have NO factory foglights, simply take out fuse 15. If you have factory foglights, check the how to on the forum to disable them.
If anyone needs help with HID wiring, I can help with that too. The kit I have is a 10000k, came with relay, balasts, bulbs, and all wiring for $60(shop here in Indiana I get killer deals at) I am also running just a black housing projector 4x6, paid $80 for them new. For $140 for HID and headlights.