4 Headlight mod (99-02 only)
This modification is possible on most years. Basically, the way stock headlights work is when you click on the high beams, the low beams click off. Like this:
Low beam:
Yellow wire – at resting state “off” is 12V+, drops to ground when turned “on”
Orange wire – remains at 12V+ constantly
High beam:
Purple wire – at rest “off” is 12V+, drops to ground when turned “on”
Orange wire – remains at 12V+ constantly
I live out in the country and having the ability to have all four lights on in the “high” mode would be awesome. All too often I see deer just dying to throw themselves at my truck. If I could light up a lonely road, maybe I could anticipate it better.
I googled how to do this on my truck and this is what I found out.
1. Open hood
2. Remove brace from firewall to Driver’s side fender.
3. Remove top of Circuit panel.
4. Unhook the snaps from the passenger and drivers side of the cover.
5. Roll entire circuit board over towards the passenger side.
6. Locate the Grey connector. (There is only one)
7. At location D3 (3rd down 4th to the right) is a light gauge yellow wire. It is the only yellow wire in this row.
8. Tap this wire and ground it to the Light ground on the firewall. Follow the lead from the Hood mounted light, and you will find it …just to the left of the Master Cylinder.
9. Put your stuff back together.
I found the information here:
Quad Headlights Mod
This sounds simple enough. While I have the headlight assemblies out for the Euro upgrade, I plan on making this mod.
Project "Charlie Murphy" 
Why not go this route instead of that one which involves way too much stuff..
take regular power relay ( 4 or 5 pin will work fine )
ground the relay side to chassis. Hook power side of relay to the high beams.
on the main relay connector (feed) hook it to the battery +
on the output side, hook it to the positive side of the dim lights.
test for correct connections on the relay.
I have done this on several fords and chevy’s, and even a couple Toyotas. no problems at all.
Never melted a housing, never had any heat issues at all. If you are concerned with heat in the housing unit, slide the housing out, and on the BOTTOM side, drill 1 or 2 small holes. This will allow some of the heat to escape out the vents, and also allow passing air when driving to cause a bit of a vacuum to pull the heat out.
As I stated, never have had an issue with anything I have driven with this setup.
Key thing in all this is to get your power source for the dim lights from the BATTERY, not the high beam wiring. So much simpler and easier.
December 27, 2013 at 11:01