24 L5P deleted now lighting issues

Bhick90

New member
Apr 26, 2026
4
4
3
Canada
I recently got my 24 L5P deleted drive it for a few days without issue and now it’s like all my lighting is glitching out. Every 5-7 seconds the lights turn on for a second then turning back off. If the lights are on then it’s the opposite they shut off for a second then come on. Some lights mirror lights headlights all of them.
I checked the battery terminals and made sure everything was tight. I tested it with truc running or accessory mode with truck not running and it does it no matter what. I also tried manually turning the lights on and it still does it. I’m at a loss for why this is happening. Has anyone had this happen and have a fix.
 

TheBac

Why do I keep doing this?
Staff member
Apr 19, 2008
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Mid Michigan
Take it back to the shop. Its their responsibility. More than likely they disturbed something in the harness or fusebox that has now become an issue.
 

1FastBrick

Well-known member
Dec 1, 2016
3,304
1,616
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Junkyard
Well if the light issue wasn't present before, something changed.

I dont know how they flash the ECU on the new trucks but if it was removed to be bench flashed they could have bent a pin re-installing it.

If it was flashed over the OBD2 port maybe it corrupted something else causing the issue.
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,817
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Larsen, Wisconsin
Well if the light issue wasn't present before, something changed.

I dont know how they flash the ECU on the new trucks but if it was removed to be bench flashed they could have bent a pin re-installing it.

If it was flashed over the OBD2 port maybe it corrupted something else causing the issue.
At this time the modules (ECM/TCM) must be removed from the truck and sent to HPTuners for 24+ Duramax.

I'm with you, I'm guessing they bent a pin or something in their file is pissing the truck off overall. I've seen some files from lower-quality sources do dumb stuff (never this issue).
 
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Bhick90

New member
Apr 26, 2026
4
4
3
Canada
I checked voltage on the truck and the batteries were reading lower than normal voltage. I am guessing that from the truck sitting outside for quite awhile in the cold while the ECM was shipped to HP tuners it damaged the batteries. Got the batteries replaced and now the truck seems to be good again and no lighting issues.