Hello, First post here, looking for some troubleshooting advice.

2015 Yukon XL SLT, 160k miles.

~3 months ago i installed the LED H11 from Headlight revolution, GTR brand, I didn't have any problems with them until yesterday driving i had issues with both low beams turning off during driving, when turning the headlight switch to off/parking/on/auto it would sometimes resolve, sometimes not.

Today during testing i was able to recreate the problem and noticed it only occurs with driving, ie bumps or some type of change in engine speed/eletrical system load as it does not happen when the vehicle is parked with the headlights on and engine running.

I also noticed at the headlight that was off the voltage was ~7.5VDC, when on it was ~12.5VDC (Measured at the molex connector with bulb unplugged).

Both headlights come back on with turning the vehicle off/on again.

Any thoughts on where to begin trouble shooting would be appreciated, so far it looks like it may be an issue with the body control module (?), is it possible to isolate that or troubleshoot it?

I changed the 2 fuses @ 121/122 labeled lt/rt HID headlight and still no dice.

I did notice it seems to turn off with bumps, and it almost seems to turn back on with RPM in park, as well as the fog lights were on when the headlights were off, but they were flickering/not consistent - It keeps point to a voltage issue for me but when i measure V at the battery/engine on its ~15V... I guess this could also be related to vibrations?

Any ideas where there could be a loose connection??

 

Welcome to the forum. I'd first check the connector to the bulb. It sounds like a possible corrosion problem creating a high resistance which would then create a voltage drop at the bulb.