2015 Sierra 1500 High-beam headlights not working..

Dave Redlin · October 26, 2019

Hello....My high-beams on my 2015 Sierra 1500 have recently stopped working. The blue light indicator on the dash works...but headlights do not 'make the sound' and high-beams don't turn on. I went to dealer and they said I have to replace the entire fuse box. They said there was some corrosion inside the fuse box and the entire thing needs replaced? I looked but didn't see much to indicate corrosion. Any other areas/ideas that might be causing the issue?

Any help/direction is greatly appreciated!

Thanks!

NCPGMC · October 28, 2019

It would seem that if such corrosion is present it would be causing other issues too...I would try to diagnose before dropping coin to replace a whole fuse box.

Start by checking the fuses and the relays that control the high beams (or others)...if there is rust one would assume the terminals on the fuses and relays would be "rusty" too or at least show signs of discoloration.

L86 All Terrain · October 28, 2019

I believe the Sierra uses a shutter in the headlight to change from lows to highs on the same H11 bulb, it could be that the shutters are stuck on the low beam setting. I had read of a similar problem on a forum where a guy's one headlight bulb was still functioning and but would not activate the shutter, he swapped out that bulb and the shutter worked fine, put in the old bulb and it wouldn't work. Not sure how the shutter system works but if it has to loop through the bulbs there could be a broken wire in the harness or not enough voltage passing through to activate the shutter. Seems odd that both would stop working but it may be a cheap thing to try out quick before dropping $500 on a fuse panel. I believe the D/S lighting harness crosses over to the P/S then back towards the firewall but I could be wrong, its been 5 years since I put in my HID's and had to mess with lights.

NCPGMC · October 28, 2019

12 minutes ago, L86 All Terrain said:

I believe the Sierra uses a shutter in the headlight to change from lows to highs on the same H11 bulb, it could be that the shutters are stuck on the low beam setting. I had read of a similar problem on a forum where a guy's one headlight bulb was still functioning and but would not activate the shutter, he swapped out that bulb and the shutter worked fine, put in the old bulb and it wouldn't work. Not sure how the shutter system works but if it has to loop through the bulbs there could be a broken wire in the harness or not enough voltage passing through to activate the shutter. Seems odd that both would stop working but it may be a cheap thing to try out quick before dropping $500 on a fuse panel. I believe the D/S lighting harness crosses over to the P/S then back towards the firewall but I could be wrong, its been 5 years since I put in my HID's and had to mess with lights.

That's true, I forget these headlights work differently than "normal" headlights...After a check in the manual and in the upfitters manual there is no separate fuse or relay for the high beams. The high beam control relays are in the underhood fuse box which are "non-serviceable Printed Circuit Board (PCB) relays and are internal to the block." There are two solenoids (right and left) that control shutters that open to let all the light "out", just as @L86 All Terrain said.

Dave Redlin · October 28, 2019

Thanks... Now that I know what to look for... searched and found information below..

"Replace the fuse block. The relays in question are integral to the fuse block and are a part of the printed circuit board itself. No serviceable part from GM. Fuse block or nothing

Would this be considered a DIY type repair?

Thanks again for the help!

L86 All Terrain · October 29, 2019

14 hours ago, Dave Redlin said:

Thanks... Now that I know what to look for... searched and found information below..

"Replace the fuse block. The relays in question are integral to the fuse block and are a part of the printed circuit board itself. No serviceable part from GM. Fuse block or nothing

Would this be considered a DIY type repair?

Thanks again for the help!

If the problem is with the PCB then yes you will have to change that fuse block. I would quickly try changing the bulbs and trying it again though before I did that. The fuse blocks are easy to remove and install. Just take a photo of your fuse placement before you pull the block out, then click the new one on and start transferring your fuses over one by one. Do not pull all your fuses from the old block, then you will be using your map to find all their homes again. There should be resources on YouTube on "pulling 2014 Silverado fuse block" if you would like more guidance.