So I've had my truck for about a year now and noticed some strange behavior from the passenger side factory LED headlights. When waking the truck up with an unlock of the FOB, the passenger headlight DRL ring will usually be slightly dimmer than the driver's side, or sometimes will be off entirely. Once the truck is started and the lights cycle during start, it'll usually be back to normal. Or sometimes when I remote start the truck, one side will be dim or off and then when I shift into drive it'll cycle the lights and then both will be full brightness. I had the dealer check it out while getting some other work done (front diff rebuild at 50k, yay extended warranty) and they assumed it was a bad housing and just replaced the headlight assembly. Surprise surprise, it still does it. I'm thinking it might be a finicky ground for the passenger side headlight harness causing intermitted high resistance to the headlight... anyone have any thoughts or can pinpoint where the particular ground in question is before I spend an hour trying to trace that out in an overly crowded engine bay? Obviously I can take it in to the dealer again, but I tend to avoid doing that for simple fixes...

 

Think it may be time to check the voltage to that light when it's off to see if it is a source issue?
Everything comes through a fully controlled module, fused and timed according to program in that module.
The module is located behind the passenger side kick panel.
Good luck.

 

I think on the newer gens, the headlights are fed from a PWM controller that is controlled by the CANBUS. I'm wondering if there is something wrong further down the line or potentially a software or sensor issue.

I don't believe it's just a straight shot of 12v to those headlights anymore.

 

Yeah so I just looked and the invoice shows they replaced the headlight assembly itself and that's it... and the LED headlights have a driver/ballast that bolts to the bottom that's actually the brains of the headlight. I mean, really, a "dumb" headlight assembly that's all LED will either work (light up) or won't (full dark), assuming it's getting sent power. Surprised the dealer went to replace the $1500 assembly without trying to swap drivers side to side first to troubleshoot. Likely I'll just buy one off ebay for $100 and swap it myself to save a trip to the dealer and a $100 extended warranty deductible.

 

I would discuss this with the dealer - they did not repair it properly and they should make it right without a new deductible.