These instructions apply to the GMC Sierra 1500 Mk4 (T1XX) 2019-Present.
For other models, please choose your vehicle here.
Before wiring work on a 2019-or-later GMC Sierra 1500, disconnect the 12 V battery — negative off first, negative on last. The T1XX adds a wrinkle: Stop/Start trucks carry an AGM battery and route the negative through a sensor stud rather than the bare post.
- Ignition off, key out, doors shut briefly. Eye protection on; don’t disconnect with the ignition on or in retained-accessory mode.
- Check for Stop/Start (2.7L turbo, 5.3L L84, 6.2L, 3.0L diesel) — those use an AGM battery; replace only with AGM.
- Open the hood; the battery is engine-bay, driver’s side (diesels add a second battery at the passenger-side rear).
- On Stop/Start trucks, undo the nut at the negative sensor stud and lift the cable off; on other trucks take the negative clamp off the post. Insulate it.
- Do the work, then reconnect the negative last, using the original nut and a hand tool only — no impact gun, no grease on the stud.
- Switch on, check for lights, reset the clock and presets.
FAQ
Can I fit a standard battery?
Not on a Stop/Start Sierra — it needs AGM; a conventional battery wears out early there.
What’s the sensor stud about?
A current sensor on the negative cable lets the truck manage charging. Reconnect to that stud with the factory nut so the sensor still reads correctly.
Why not an impact wrench?
Over-torquing the stud nut can damage the sensor; snug it by hand.
What resets after?
Clock and presets. A warning light that lingers means scan the code.
The GMC Sierra 1500 is mechanically identical to the Chevrolet Silverado 1500, so this procedure is the same on both trucks — see our Chevrolet Silverado 1500 guides.
If your Sierra logs a trouble code with the warning light, decode it on autodtcs.com.
Independent guide — not affiliated with GMC. Always follow your official service manual and safety precautions. Read our full disclaimer.