Tanner Posted March 28, 2016 Share Posted March 28, 2016 Is there a write up on the headlight relay upgrade? I have been searching for it but yielded no results. Thanks Link to comment Share on other sites More sharing options...
benjy_26 Posted March 28, 2016 Share Posted March 28, 2016 http://jeep-xj.info/HowtoHeadlightLoom.htm Link to comment Share on other sites More sharing options...
Megadan Posted March 28, 2016 Share Posted March 28, 2016 You can do that write up ^^Or buy a Putco harness. http://www.amazon.com/Putco-230004HW-Premium-Automotive-Lighting/dp/B001P29X4GIn either case, it's pretty simple. Link to comment Share on other sites More sharing options...
mikekaz1 Posted March 28, 2016 Share Posted March 28, 2016 the putco harness is easier and neater then most DIY jobs. but for the $5 cost to DIY vs $40 for the putco, I just made my own. Link to comment Share on other sites More sharing options...
Rockfrog Posted March 28, 2016 Share Posted March 28, 2016 or $10 for an ebay harness, be sure to get the ceramic plugs, and ensure that it uses standard relays. The putco uses Honda relays, which some have found difficult to find. I have a Putco on my XJ, and an ebay harness on my MJ ... both are equal in quality (both in wire size/quality and build quality), but the use of standard bosch style relays makes for the win on the ebay harness. Given the $10 ebay price it makes it even simpler, and cheaper than making your own (considering time to build as a cost). In any event, if you have a harness it's only three connections (batt + and two grounds) and mounting the relays. Another plus for the ebay harness I got was it used a ganged relay block similar to the renix relay blocks. Less holes and they stay put (they even mated up to the stock relay blocks if one were so inclined). The rest is just running the harness behind the grill panel and into the headlights. Just did the XJ last week and it took all of about 30 minutes since I re-painted the headlight buckets "since I was", and went "the extra mile" with wire routings. Link to comment Share on other sites More sharing options...
Tanner Posted March 30, 2016 Author Share Posted March 30, 2016 Thanks for the help guys, just what I needed! Link to comment Share on other sites More sharing options...
gogmorgo Posted March 31, 2016 Share Posted March 31, 2016 (edited) This is a crude wiring diagram I put together based on the how-to above. I had trouble wrapping my head around his instructions until I sat down and worked this out. http://i.imgur.com/LiQd7xu.png The wire gauges are overkill for the factory ~60W bulbs by a factor of about triple, but I figured it would let me significantly upgrade the bulbs later. Except after doing the upgrade I decided I didn't really need anything more than factory. It also made me feel better about using relays rated for 30amps which will handle 300 W at 12V. I'm also confident that the 14awg is waaaay overkill just to trigger relays but I had a bunch sitting around already. Using AR274 relays as recommended in the write-up and running separate 12V feed wires from the battery for each relay will eliminate the need for three-way splicing. The above configuration should allow for running 90W/bulb, maintaining the 15 amp fuses as the weak links. 25A fuses would allow for 150W/bulb, and in theory a 30A fuse would allow for 180W/bulb but you'd also want to upgrade the relays at that point so you're not fusing at the maximum recommended load on any given component, which is what the relay harness is trying to avoid in the first place. Editing to update the now broken URL to Go Jeep’s write up: http://gojeep.willyshotrod.com/HowtoHeadlightLoom.htm Edited May 28, 2023 by gogmorgo Link to comment Share on other sites More sharing options...
Tanner Posted March 31, 2016 Author Share Posted March 31, 2016 This ☝is awesome. I appreciate it! Link to comment Share on other sites More sharing options...
gogmorgo Posted March 31, 2016 Share Posted March 31, 2016 :thumbsup: Link to comment Share on other sites More sharing options...
Mattman6 Posted March 31, 2016 Share Posted March 31, 2016 or $10 for an ebay harness, be sure to get the ceramic plugs, and ensure that it uses standard relays. The putco uses Honda relays, which some have found difficult to find. I have a Putco on my XJ, and an ebay harness on my MJ ... both are equal in quality (both in wire size/quality and build quality), but the use of standard bosch style relays makes for the win on the ebay harness. Given the $10 ebay price it makes it even simpler, and cheaper than making your own (considering time to build as a cost). In any event, if you have a harness it's only three connections (batt + and two grounds) and mounting the relays. Another plus for the ebay harness I got was it used a ganged relay block similar to the renix relay blocks. Less holes and they stay put (they even mated up to the stock relay blocks if one were so inclined). The rest is just running the harness behind the grill panel and into the headlights. Just did the XJ last week and it took all of about 30 minutes since I re-painted the headlight buckets "since I was", and went "the extra mile" with wire routings. Can you post a link to this eBay harness Link to comment Share on other sites More sharing options...
benjy_26 Posted March 31, 2016 Share Posted March 31, 2016 This is a crude wiring diagram I put together based on the how-to above. I had trouble wrapping my head around his instructions until I sat down and worked this out. The wire gauges are overkill for the factory ~60W bulbs by a factor of about triple, but I figured it would let me significantly upgrade the bulbs later. Except after doing the upgrade I decided I didn't really need anything more than factory. It also made me feel better about using relays rated for 30amps which will handle 300 W at 12V. I'm also confident that the 14awg is waaaay overkill just to trigger relays but I had a bunch sitting around already. Using AR274 relays as recommended in the write-up and running separate 12V feed wires from the battery for each relay will eliminate the need for three-way splicing. The above configuration should allow for running 90W/bulb, maintaining the 15 amp fuses as the weak links. 25A fuses would allow for 150W/bulb, and in theory a 30A fuse would allow for 180W/bulb but you'd also want to upgrade the relays at that point so you're not fusing at the maximum recommended load on any given component, which is what the relay harness is trying to avoid in the first place. Pretty much looks like what I built, except I used 8ga wire for the grounds. I had a bunch laying about... Link to comment Share on other sites More sharing options...
gogmorgo Posted March 31, 2016 Share Posted March 31, 2016 Yeah, it's a pretty basic relay harness. You can complicate it as much as you want but why add cost and complexity if you don't have to? My research (i.e. 30 seconds with google) indicated the 10awg should be good for ~50A, so around 600W @12V. I was initially going to go with 8awg for the main power wires, but the significant jump in cost from 10awg wasn't worth it to me when I already knew the 10awg was overkill. Can't fathom ever exceeding 200W bulbs, as I'm pretty sure you'd be cooking the buckets at that point, and frankly that's pretty unreasonable for a focused lamp... you'd be blinding yourself let alone oncoming traffic. Link to comment Share on other sites More sharing options...
benjy_26 Posted April 1, 2016 Share Posted April 1, 2016 Agreed, Gog. I'm using Sylvania Xtravision H4's in mine and don't see the need for a hotter bulb (even though I can totally run them). As it is, folks keep asking me if I threw in a HID conversion. Link to comment Share on other sites More sharing options...
LarryH88bt Posted June 2, 2016 Share Posted June 2, 2016 I'm looking to do this but I'm not good at electrical. It just doesn't click in my brain like other things. Where/how does the new harness wire into the switch to turn em on/off? With all the wires snaking around under the hood and dash it seems easier to just do an entirely new switch than using the factory plunger switch. I have a Renix if that matters. Link to comment Share on other sites More sharing options...
Rockfrog Posted June 2, 2016 Share Posted June 2, 2016 It plugs into the stock headlight plug. The only thing you have to do is decide where you mount the relays, and connect two ground wires to the body (generally at an existing bolt), and connect the red wire to the battery. It's that simple, it uses the stock system to trigger the relays that supply power directly from the battery to the headlights. Savvy? Sent from my SGH-I337M using Tapatalk Link to comment Share on other sites More sharing options...
LarryH88bt Posted June 3, 2016 Share Posted June 3, 2016 Ok, I think I got it, thanks. Link to comment Share on other sites More sharing options...
Rockfrog Posted June 3, 2016 Share Posted June 3, 2016 When you have it in your hands it'll make more sense. Sent from my SGH-I337M using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted June 3, 2016 Share Posted June 3, 2016 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 Link to comment Share on other sites More sharing options...
87mjdriver Posted June 6, 2016 Share Posted June 6, 2016 look up Ksuspensionlifts, they have a well made harness for 30$ Link to comment Share on other sites More sharing options...
a bum with money Posted August 8, 2016 Share Posted August 8, 2016 I like how you guys made it clear as to how to diy instructions, especially the drawn wiring diagram. :thumbsup: but why is the second rh socket (old) still in the loop? wouldn't that be eliminated? :???: bryce Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 8, 2016 Share Posted August 8, 2016 Nope. That socket is where the new harness gets the HI - LO beam feeds from the existing headlamp dimmer switch to trigger the relays. Link to comment Share on other sites More sharing options...
87MJTIM Posted August 8, 2016 Share Posted August 8, 2016 Did this upgrade to both my MJ and CJ. Simple P-N-P. It does require drilling holes to mount the relays. The most fiddly part is running wires from right to left side of the grill. Link to comment Share on other sites More sharing options...
a bum with money Posted August 8, 2016 Share Posted August 8, 2016 not to sound like an idiot, you cut-out the old plug and splice in the leads from the h/l switch. correct? Link to comment Share on other sites More sharing options...
87MJTIM Posted August 8, 2016 Share Posted August 8, 2016 No! Leave the old plugs in place. You will connect on to the new harness. This will give power to trigger the relays. Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 8, 2016 Share Posted August 8, 2016 No, you just plug in the male connector on the new harness into the old headlamp female connector. You can use either the R or L headlamp connector. No cutting/splicing necessary, Link to comment Share on other sites More sharing options...
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