I picked up this headlight harness, supposed to supply more power to it. It is compatible between 83-91 just need to splice different plugs on I guess. One says plug into current headlight harness...where would I find this? And/or a wiring diagram for the 87-91 setup?

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It looks like you simply unplug both headlights and plug one into your harness. Plug your harness onto your headlights, ground each one, then connect to battery power (preferably through a 15A breaker). Your harness may already have a fuse in it so you should be good to go. All you are doing is supplying the headlights through a relay to battery power rather than go through all of the wiring in the cab, the switch, etcv. You are eliminating the headlight load from your switch which should inprove it's life considerably. I hope this helps. I can't tell if there are two wires or just one at the power connection. The relays need a ground to work. I don't know if they use the ground at the headlights or have a dedicated wire of their own. I hope this helps.

 

Where is the harness one?

 

Whiter Whites, Brighter Brights .: Articles

GO PATS!!

 

so basically its not a plug im looking for, just need to run the wires? wiring is an absolute night mare for me lol

 

Been meaning to do this forever now... some day lol... In my defense my lights are really good for origional 77 stuff.

 

very very basic.
just look at the relays in their simple form.which is just basically a switch,but instead of requiring a manual toggle,they are switched via power (though in this case,your headlight switch and low/high beam switch becomes said toggle lol.don't let me confuse ya though,read on.)
the power that "opens" a relay,isn't the power source the device will receive.it's just the power the relay or "powered switch" if you will, will receive to open the flow from (in this case) your positive bat to the headlight.your headlight switch will control the "open/on" or "closed/off" switch.
so when following the diagrams keep this in mind is all.
all you need to accomplish is getting power directly from the battery to your headlights,the ground is constant.
think of the flow of electricity like the flow of a garden hose so you can understand what your actually doing,otherwise,you'll just be stuck looking at "wires" like the rest of the people who don't understand the flow.
you want your headlight switch just acting like a low amp draw trigger switch (like when you run the wires to control a GP relay) telling a "switch" (your relay) to open the flow of electricity from your battery to your headlights this is all.electricity needs to "exhaust" too (to keep it simple) ,for this it has the ground (ground is never switched.)
pretend your hot wires that your running is a water hose and look to see where it needs to flow.
pretend the ground is your safety,constant,always needs to be, exhaust system on the truck.

if you juat don't "get it",a few places make up the correct wiring harness relay that is plug and play.im not sure what you have there.personally id just make that work.but,if your lost,your lost.

hey check this out '91.im working on brighter lights now too:
https://www.ford-trucks.com/forums/a...1&d=1324682562
https://www.ford-trucks.com/forums/a...1&d=1324682562

i wimped out doing the other side today due to the cold though lol.

 

ok thanks i understand that so i guess whats really throwing me off is the 3 prong plug on the harness above that reads "plug into existing harness" so look at the far right plug in this picture...thats whats throwing me off

 

The one with the 3 male terminals plugs (looks like the back of the headlight bulb) into the OEM FORD harness to signal the relays when to close.

PS: If you would show us the labels we could be more exact in telling you what to do.

 

lol i like how the only other things in your picture other than your wireing harness is a heavy log chain and a big hammer...

 

I installed a pair of Silverstars and they work great. Bright as hell, they're actually much brighter than the lights in my PSD. A significant improvement.


HELL YEAH!

 

If you're behind those Silverstars they are brighter. The problem is when you are coming at those things. I hate them! Think about it, facing those things is not pleasant.I know it's not illegal to use them, but it should be. Pay attention the next time you're running at night, you'll see what I mean. They are irritating.

 

i installed some HID's in my truck (you know the crazy bright white ones) i used to hate them but once you have them you learn to love them you can clearly see the whole road for a good half mile or more

 

I know it's really good for you, but think about the guy coming at you.

 

how ya doing there 91?
don't give up.it sure is worth it!
i just finished up mine tonight.i had the relay mod and updated bulbs,but holy crap i didn't know my lenses where that yellowed!
it made the bulbs and relays finally show their magic.so if you don't see a major improvement,it could be your lenses fyi.
it's so nice to be able to see at night! now my headlights are even better than my plow lights! and those are great.
bright white.no more tinted yellow candle path lmao! there's a whole road out there at night! who knew! lol.