Wiring diagram for LED headlight conversion

[redneck_adjacent]

There are countless threads online about 4656 to H4 LED headlight conversions. Usually, those threads make two recommendations: swap pins two and three in the OEM headlight connector; invest in one of the many conversion kits from Amazon, Summit, etc. Those threads usually clarify that the former method of swapping pins two and three only allows the low beams to operate but not the high beams. The latter method works but I have not found any threads which explicate how exactly they work. While most hobbyist mechanics seem to have no problem with miscellaneous relays hanging all over their engine bay, some of us centrally manage and organize our electronics in an auxiliary fuse / relay box. The purpose of this post is to help those noble souls who manage their electronics in an organized fashion with a DIY solution to the 4656 to H4 LED headlight conversion.

The wiring diagram below (made by me) uses two relays per headlight. You could use just two relays for both headlights; however, that means both headlights will be inoperable if a fuse or relay blows.

Second, as noted in the bottom left of the diagram, connector 4656 does not match the factory connector. You will need to swap pins two and three in your model if your vehicle uses the factory configuration. If you are wondering why mine is different -- that is none of your business. I am a private person.

Lastly, the below diagram was not only bench tested and proven to work properly -- it is how I wired the headlights on my truck.

 

[Rock62]

Keep in mind when driving it freezing rain, sleet or any wet conditions in the 28-34 F temperature range. Any moisture will tend to freeze on contact. LED lights do not generate enough heat to keep the lens free of ice.

 

[tacojoel]

Neither do these incandescent headlight bulbs these trucks come with. The plastic headlight lens, and stupid nanny grill sensor drove me crazy during a bad freezing rain storm more than once during winter. Don't even get me started on my trucks ice covered predator bars during the 1st winter I had them on my truck that I nearly broke my neck on them.

 

[redneck_adjacent]

Keep in mind when driving it freezing rain, sleet or any wet conditions in the 28-34 F temperature range. Any moisture will tend to freeze on contact. LED lights do not generate enough heat to keep the lens free of ice.

There are plenty of LED headlights designed to deal with that problem, e.g. JW Speaker 8910 Evo 2’s. Regardless, OEM halogen headlights have this problem, too, so I am failing to see your point.

 

[JayQQ97]

Neither do these incandescent headlight bulbs these trucks come with. The plastic headlight lens, and stupid nanny grill sensor drove me crazy during a bad freezing rain storm more than once during winter. Don't even get me started on my trucks ice covered predator bars during the 1st winter I had them on my truck that I nearly broke my neck on them.

My trucks sealed-beam halogens barely survived a long slushy highway wheel through unsalted sloppy slush that sprayed over and froze in the wind
I have those pics somewhere of the aftermath

 

[JayQQ97]

My trucks sealed-beam halogens barely survived a long slushy highway wheel through unsalted sloppy slush that sprayed over and froze in the wind
I have those pics somewhere of the aftermath

 

[tacojoel]

The non led headlights on my 2020 taco looked as bad, or worse during a trip to northern ma. 2 winters ago after getting hammered in snow squalls all the way up to mt greylock.

 

[redneck_adjacent]

They are expensive but check out the JW Speaker 8910 Evo 2's, fellas. They have heating technology specifically for melting ice. I learned about them from lurking on trucker forums.

As a disclaimer, I have a rare genetic condition which impacts my vision at nighttime. Consequently, I do a lot of research into lighting so I like to think that means my suggestions when it comes to lighting are decent.

On that point, I am actually deleting the KC HiLites fog and flood lights from my truck in favor of the Baja Designs LP6 Pro soon. I wanted an auxiliary lighting system that does a little bit of everything, reduces the number of wires, relays, and switches in my cabin, and cuts through fog like butter. The fog lights and flood lights are great but add a lot of complexity in terms of switches and wires. Anyway, if any of you are interested in buying my KC lights then reach out. Else, they're going on Ebay.