Headlight Wiring Harness Questions

[SBpunk]

Ok maybe I'm a moron or I bought the wrong harness. Got a putco harness and thought it would be a quick and easy upgrade. Not so much. Anyone explain this to me in dummy steps? I already have my entire harness out but I'm not seeing how any of this matches up.

 

 

Figured this would be what I unplugged but yeah not even close to matching

 

And here is the harness

[cruiser54]

It's not a REPLACEMENT harness. It's a SUPPLEMENTAL harness.

 

Cruiser’s Headlight Upgrade Harness Instructions

It's easy to install a supplemental headlight harness.

From the factory, the voltage to the headlight bulbs travels from the battery, inside the cabin, to the headlamp switch, and then back out to the lamps via undersized wire. It's not uncommon to find only 10.5 volts at the lamps.

The supplemental harness is installed so that it provides battery voltage to the lamps and is just triggered by the factory wiring. The result is about 30% brighter headlamps and headlight switches that don't melt and burn out.

Absolutely plug and play. Remove grille and headlamp bulbs. I fed my harnesses from the passenger side starting between the battery and the back of the headlamp housing, over to the driver side. Plug the driver side bulb into the new harness. Attach the new harness's ground wire under one of the small bolts on the radiator support after scraping the paint off under it. Attach the harness to the existing harness behind the grille working toward the passenger side. . Plug the new harness plug into passenger headlamp. Plug original headlamp plug into receptacle on new harness. Attach the ground for the passenger side just like you did the driver side under a radiator support bolt. Attach relays with provided bracket on the passenger side inner fender. Connect power wires to battery.

Revised 12/10/2012

[SBpunk]

Ok just to make sure I'm reading this right because it doesnt look right when I stare at the harness.

 

Feed new harness in passenger side

Plug in new harness MALE 3 prong into old harness passenger side headlight connection

Plug driver side and  passenger side new harness headlight connections into light housing

Leave OLD driver side headlight connection dangling somewheres?

[HOrnbrod]

It looks like the correct relay harness. You are not supposed to pull your original harness. The original harness remains intact and is only used to trigger the relays on the new harness. The original harness right headlamp connector plugs into the new harness, the cabin HI and LO beam switch trigger the appropriate relay, and the the new harness feeds the relay output to your headlamps.

[SBpunk]

Yeah I figured it out. I just mis understood. Got it working. Sucks u thought it was a replacement

[cruiser54]

Yeah I figured it out. I just mis understood. Got it working. Sucks u thought it was a replacement

It's in the writeups which can be found by clicking the link below in my signature. Might wanna take a look at those for future reference.

[SBpunk]

I read it before posting Cruiser just got confused when I looked at the actual harness. I was under the impression it was a complete replacement. Once I figured out that one of the headlight plugs on the old harness just arent used it  clicked. Too bad it didnt happen before i pulled the entire fkn harness lol

[Rohls]

Hi, so I'm looking around to upgrade my harness and headlights. I'm going for the Hellas E-codes. I'm trying to purchase the harness, but there are a disturbing number of negative reviews on amazon....Putco 230004HW Premium Automotive Lighting Wiring H4 100W Heavy Duty Harness and Relay

 

 

Thoughts if cheap relays, poor crimps, no inline fuse and improper gauge wire worry me.

 

Is there a more quality plug and play harness somewhere?

 

Or does someone have an easy to follow schematic u can piece a harness together with?

 

Thanks.

[gogmorgo]

http://jeep-xj.info/HowtoHeadlightLoom.htm

This is what I followed when I put mine together. Total material cost for me was around $75, but that's up here North of the 49th, and I got enough wire and connectors to make at least three harnesses cause I bought things in bulk. The relays he suggests, AR274, were kinda pricey, so I just used a couple "normal" relays (at around 1/5th of the cost). The difference is having to splice the one output to two headlights verses having two outputs from the relays.

I've got a wiring diagram that I drew up quickly that I can upload if you want, but it's a pretty simple diagram. His instructions are decent, but I made the diagram to help me visualize things a bit better.

Also, he's Australian, so his vocabulary can be a bit foreign and all his measurements are metric. I think I converted all the measurements on the diagram I made. I'll go on a bit of a hunt to see if I can find it.

 

Edit: he moved his website. New link is: http://gojeep.willyshotrod.com/HowtoHeadlightLoom.htm

Edited May 28, 2023 by gogmorgo
Adding broken link

[cruiser54]

Hi, so I'm looking around to upgrade my harness and headlights. I'm going for the Hellas E-codes. I'm trying to purchase the harness, but there are a disturbing number of negative reviews on amazon....Putco 230004HW Premium Automotive Lighting Wiring H4 100W Heavy Duty Harness and Relay

 

 

Thoughts if cheap relays, poor crimps, no inline fuse and improper gauge wire worry me.

 

Is there a more quality plug and play harness somewhere?

 

Or does someone have an easy to follow schematic u can piece a harness together with?

 

Thanks.

I've installed more than 4 Putcos with no issues after years of use.

 

My theory is that the grounds were insufficient and that caused the relays to get hot and fail. That, and people locating the relays so moisture could get in.Bare metal ground points!!

[HOrnbrod]

I've had their harness on for about seven years now switching the Hella E-codes. Zero problems. The only thing I don't like about it is the horrible yellow wire loom.

[cruiser54]

I've had their harness on for about seven years now switching the Hella E-codes. Zero problems. The only thing I don't like about it is the horrible yellow wire loom.

BLACK split loom and extra careful routing......

[HOrnbrod]

That's what I did, but why in hell did they have to use yellow? Must have been all they had in China when they made them up. The only yellow I want to see on my truck is on the shocks.  

[cruiser54]

Cousin WunHungLow had a surplus of yellow insulation left over from his bomb making days. 

[gogmorgo]

http://jeep-xj.info/HowtoHeadlightLoom.htm

This is what I followed when I put mine together. Total material cost for me was around $75, but that's up here North of the 49th, and I got enough wire and connectors to make at least three harnesses cause I bought things in bulk. The relays he suggests, AR274, were kinda pricey, so I just used a couple "normal" relays (at around 1/5th of the cost). The difference is having to splice the one output to two headlights verses having two outputs from the relays.

I've got a wiring diagram that I drew up quickly that I can upload if you want, but it's a pretty simple diagram. His instructions are decent, but I made the diagram to help me visualize things a bit better.

Also, he's Australian, so his vocabulary can be a bit foreign and all his measurements are metric. I think I converted all the measurements on the diagram I made. I'll go on a bit of a hunt to see if I can find it.

Found my diagram, but didn't want to scan it cause it somehow wound up soaked in ATF. So instead I made this:

[HOrnbrod]

:thumbsup:

[gogmorgo]

I'll also add that I only made my own because I needed one "now", and not "two weeks from now" which was the fastest estimated shipping time unless I wanted to pay exorbitant shipping fees. Sure, I know it's made properly and is likely better quality than the Putco (and also doesn't have YELLOW!!!) but electrical stuff is probably my least favourite automotive-related task after upholstery. I would have gone with the Putco if I didn't need lights that wouldn't set my truck on fire before I could drive home from school that evening.

[Rohls]

You guys rock! Thanks for the tips. I will be making my own black harness shortly:)

 

also, do the 'old bulb holders' just hang out when this new harness is installed..? Kinda seems like it from the above diagram.

[gogmorgo]

Yes, the original harness is left intact, and you plug the new one into the original passenger side headlight socket. The new harness goes between the old harness and the headlight bulbs.

[87MJTIM]

Same question; different thread.

 

Alright. After reading and re-reading CC and other Jeep forums about the lighting upgrade, I now understand it is not a replacement wiring harness, but a supplemental harness.

 

This got me thinking of doing the same upgrade to my 84 CJ7.

 

The question I have is the wiring harness long enough to stretch from the battery - passenger's side firewall - to the driver's headlight?

[gogmorgo]

The xj/mj harnesses probably won't be long enough to make it all the way to the firewall on either side. But it's pretty easy to cut and splice in more wire for more length.

You may also be able to buy a harness for the cj7.

[gogmorgo]

Sorry, better answers in the other thread. Didn't see it before I posted.

My above answer is based off gojeep's diy measurements.

[87MJTIM]

FINALLY GOT THE UPGRADE DONE!

 

This was a relatively easy process.

 

Original lights, low beam

 

After upgrade, low beam

 

Before, high beam

 

After, high beam

 

I have not taken it out on the road yet. 

[cruiser54]

FINALLY GOT THE UPGRADE DONE!

 

This was a relatively easy process.

 

Original lights, low beam

 

After upgrade, low beam

 

Before, high beam

 

After, high beam

 

I have not taken it out on the road yet. 

You will love it. Harness is the FIRST thing to be done.

[87MJTIM]

It was both the harnness and headlights.