Headlight harness is smokin' relays

[chewie14]

So I have a 91 and a 94 XJ in which I installed Hella H4 housings and Sylvania Ultrastar bulbs with the headlight upgrade harness from K Suspension on both vehicles. Works flawlessly!

I also have a 96 XJ where sometimes the headlights will shut off and I hear a click behind the gauge cluster and then they come right back on after about a second or two. I figured the lights were overloading a breaker or something up under the dash. So, I installed the same setup on my 96 XJ, the new harness and H4 lights, and It does nothing but smoke relays. It seems when I switch to high beams, that's when it starts letting the smoke out of the relays. Does the high/low beam switch work differently on the 96 versus the 91 and 94? It all works just fine and great between high and low without the upgraded harness, but headlights shut off after a while, which is why I want the new harness to take the heavy load off the system, but when I add in that new harness, it just goes through relays instantly like candy. Something somewhere is creating an instant dead short and I can't quite figure it out. But, no fuses are blown! Just cooking relays! I know if I went to LED lights, wired stock with no upgraded harness, I wouldn't overload stuff and it would work but I hate LED lights. Any ideas?

 

[Jeevy]

Did you replace the relay under your dash you heard clicking? If not it may have shorted and is grounding and overloading the other relay’s. Other than that the only other thing I know of would be grounds, make sure those are good with no rust underneath them. Hope this helps, good luck keep us posted on what it was

 

[Anak]

I know nothing about the K-suspension system, but I have put my '96 XJ's headlights on relays and it works flawlessly. I used relays from Daniel Stern Lighting, but I don't believe that would make any meaningful difference. I spliced into the headlight harness in order to trigger the relays and ran new wiring into new headlight sockets. I don't know if the K-suspension system works any differently, but I doubt there is a difference between '96 and the previous H.O. years when it comes to the headlight switch.

A poor quality ground to your relays sounds like a good place to start. If not that, then the ground for the headlights themselves. Somewhere you have a bad connection.

 

[Tim_MN]

I use Honda relays in both my XJ's. The less expensive H-4 wire harnesses usually use cheap Chineseium relays.

 

[chewie14]

Thanks for your replies, guys! I'll dive into it hopefully sooner than later because I need to drive this rig at night. I'll keep you guys updated as to what I find, it might be a little bit before I can get to it though! Thanks everybody!

 

[ChillyB]

When I replaced headlights with white Sylvania incandescent bulbs my 95 lights started turning off after 15 min of driving. Messing with switch would cause them to temporarily work again. I installed a harness relay kit (the expensive one made in USA, Jeep Cables?) And problem went away.

I suspect the brighter lights were harming my headlight switch. The 95 doesn't have a factory headlight relay. Watched vids where the switch develops hot spots from high resistance, which melts the harness plug. Maybe yours reached that point?

I think taking the high current load out of the dash switch is a good idea for every old vehicle.

 

[chewie14]

Thank you for your reply! I'm sure the high load causing issues is what's going on, which is why I wanted the harness. I still have yet to check the actual switch, but when I installed the harness relay kit, it smokes the relays in it when I hit the dimmer switch. But it doesn't smoke the relays in my harness relay kits in my other Jeeps.

Maybe there's some goofiness going on in the dimmer switch that causes the relays to instantly smoke on the relay harness when I hit the dimmer switch. They'll stay on, but the second I switch the dimmer switch, they let the smoke out. I just now replaced the dimmer switch but have not had time for a test. And I'll get to the headlight switch soon. Also going to investigate whatever clicking I hear behind the the speedometer, when the headlights shut off on their own, when wired stock without the relay kit. But that load should be eliminated if I can install the relay harness kit without smoking relays.

Time is an issue in my life right now as I'm working a lot and I just moved into a new shop and it's not set up yet. But I'll get there! This thread might get dragged out for a considerable length of time... Hahaha. Thank you!