2016 Sierra Headlights Turn Off At Night And Instrument Cluster Go Full Brightness

[spayne460]

Long story short. 2016 GMC Sierra SLT 4X4 Z71 crew cab. When driving at night everything is normal. Lights work fine and instrument cluster is normal. After 5 to 10 minutes the headlights turn off, fog lights stay on and the instrument cluster goes to full brightness. The dimmer switch will control the HVAC and other interior lights normally, the cluster stays full bright and tbh I think it's much brighter than normal. The headlights will turn on with the manual headlight switch but the cluster stays full bright. After 5-10 minutes the cluster will go back to normal and the auto headlights work normally. This cycles randomly and only happens at night.

 

I pulled the test procedure and tested out the light sensor on the dash. It tested good, but I replaced it anyway 3 times with dealer parts. I replaced the BCM, I replaced the instrument cluster. The only thing that is next is the hvac module that the light sensor runs through. I can program the modules and they are relatively cheap on rock auto so throwing parts isn't that much of an issue for me, but I am getting tired of dealing with this. Has anyone ran across this and found a fix?

Edited October 20, 2025 by spayne460

[mikeyk101]

Instead of throwing parts at it, have you gone through "ALL" the grounds? There are several that are connected to body as well as the infamous G214 that you can find under the dash speaker on left side of dash. Especially on the 2014-15, it is a known issue and isn't always a clean ground and the insulation may need to be cleared away from the stud.  Bad grounds cause all kinds of intermittent problems. Also an old weak battery will also cause problems. Make sure to also check the main negative cable coming off the battery.

Edited October 19, 2025 by mikeyk101

[rav3]

I would start with what mikeyk101 said...

[spayne460]

23 hours ago, mikeyk101 said:

Instead of throwing parts at it, have you gone through "ALL" the grounds? There are several that are connected to body as well as the infamous G214 that you can find under the dash speaker on left side of dash. Especially on the 2014-15, it is a known issue and isn't always a clean ground and the insulation may need to be cleared away from the stud.  Bad grounds cause all kinds of intermittent problems. Also an old weak battery will also cause problems. Make sure to also check the main negative cable coming off the battery.

I have checked these grounds. The problem is not intermittent enough to be grounds. It's pretty predictable. But yes body grounds to the frame and the one under the speaker. I could see if it was you hit a bump and it would start/stop but this is pretty consistent. I had some codes for the front view camera so I replaced it too. One piece of info I forgot to add is that I had a power tap to the mirror for a radar detector. I think that messed up the front camera and might have started all this. My next step is the HVAC module behind the glove box.