If you drive a GMT800, you already know how reliable and well-built these trucks are. One area GM definitely fell short on though is the reverse light output. The factory backup bulbs are weak, and even on a stock truck with no tint it can be hard to see when backing up — especially since these trucks and SUVs never came with factory backup cameras. Add tinted windows and visibility gets even worse. At that point it becomes more than an inconvenience; it’s a real safety issue when you can’t clearly see what’s behind you.
The good news is the upgrade is extremely simple. Each taillight is held in with two Phillips screws per side — just take your time so you don’t strip them — and the housings pull straight out. Anytime the taillights are off, it’s worth cleaning the dirt out from behind them and spraying some WoolWax or Fluid Film in there for rust prevention.
For bulbs, ditch the factory 3157 halogens and switch to LEDs. They draw less power and the light output difference is huge. Aim for something in the 3000–4000 lumen range with a projector-style design so the light actually throws backward instead of just glowing inside the housing when you’re backing up.
I’ve had good luck with Auxito bulbs in the past and have tried a few different styles. They seem to last; I have some still running good after 5 years!
The first style that I’ve had good success with is the non-projector version. Link to the bulbs here.
These bulbs do not have a lense on them, but are still super bright.
I’ve also had good luck with the “projector” style lens. The clear rounded dome on the tip focuses and throws the light backward instead of letting it scatter inside the taillight housing like a standard LED or halogen. That lens is what gives it the “projector” effect and improves usable light when reversing. If you want the best light output possible from factory taillights; opt for these “projector” style bulbs. Link to the bulbs here.
Even in the daylight these bulbs are super noticeable and impressive!
They are even brighter at night! 
If the factory reverse lights still aren’t enough — especially with dark tint or poor nighttime visibility — consider adding a backup camera. Some cameras include built-in LED lighting which helps quite a bit when backing up in low light.
If you want maximum reverse lighting, the XD License Plate Reverse Light Bar is a solid upgrade and can be triggered off the reverse light circuit.
GMT800 trucks run two reverse bulbs. Factory halogens are roughly 21–27 watts per bulb, putting the total load around 42–54 watts. Switching the reverse bulbs to LEDs reduces the draw significantly, leaving plenty of available capacity to trigger and run a license plate reverse light bar properly.
