I let 4x4 Labs take my truck out to the FJ Summit. Everything was going well and they are almost there. However, they came out from a stop at the store and the headlights won't come back on. I have no ideas. I sent them the wire harness schematic but I really don't know what the issue could be. They said they looked at the fuses, relays etc and they look fine. They can hear it click when they flip on the high beams but no light out of either side... I know it is a shot in the dark but anybody got any ideas? It was all working normally. Weirdest thing is that i have my halos rigged up as DRL/turn signals and they get those coming on when they switch to auto but can't get the headlights to come on... I am lost.

I am here is Ouray. You mind if I take a look?

That would be helpful. Can you PM me your info and I'll pass it along to Luke? I'm not there. Luke (owner of 4x4 Labs) has my rig. He is almost there. having to risk it running my LED light bar to make it...

@bimrunner
You might want to give @TRSMatt or @TRSAndrew a call when they open, see if they can give you some input on possible failure!


Best Regards,

If both lights fail to come on you are looking for something common to both, which likely eliminates bulbs and ballasts. (Generalizing) I'd first suspect the relay which you can buy at any auto supply. Mine failed recently, after 3years.

Next, I'd suspect the 12V supply to the relay, or the ground connection for the relay.

+1. Have them thoroughly check the source connection and ground connection. Check not just the new fuse on the harness but also the fuse for the original lights as those connect to your relay. Also have them try cycling the lights off and on several times, not just the high beams (although I'm sure they already tried). Lastly, this sounds weird but have them turn off and on the truck a couple times, trying the lights each time.

Good luck.

Thanks guys. Hopefully they can get it sorted out. Thankfully they were close to their destination and only had one encounter with an understanding peace officer... I'll pass on the suggestions.

There should be two relays. One for each side. I had one fill with water and corrode the inside bits.

Not necessarily.... I only have one relay.

That's why only one side works. J/K

Thanks though, the ones I have seen only had two but now thinking about it makes sense that it could be done either way.

No worries man, please update us with what the issue was!

FWIW I also only have one relay per HID set (two total because I have quads).

I'll post as soon as I hear. I am willing to bet it is the in-line fuse though. They checked the other fuse and they say the relay clicks when they flip the high beams on but no light - which sounds like it makes sense if the in-line fuse is out since I am only currently running bi-xenon. Neither side gets light so I'm betting it is that fuse. Stay tuned... I know they are busy having fun so who knows when they will get to checking...

That sound is not likely the relay, as it picks up when you turn the lights on. The sound they're probably hearing is the high beam shutter inside the projector operating, which it does entirely independent of anything else.

Just don't get sidetracked by that like I did. That's a logical conclusion, but a bad relay gives the exact symptom - dead-ness.
UNLESS, you have 2 relays. ;~)

Before dark, I'll bet.

That is extremely useful information. I will probably recommend they run over to an auto-parts store (Napa, Orielly... whatever is out there...) and check the fuse there and if not the fuse, throw a new relay in. Seems like that would probably solve the issue completely with contingency too! Thank man!

Headlights fixed. Forgot to switch battery to dual mode and ran down with fridge so apparently lights wouldn't come on. All is right now! Ah, the simple things.