ON TWO SEPARATE OCCASIONS, THE TRUCK HAS BEEN DEAD WHEN ATTEMPTING TO CRANK. THERE WERE NO LIGHTS OR DEVICES LEFT ON AFTER THE PREVIOUS TIME THE TRUCK HAD BEEN USED. SOMETHING IS DRAWING POWER FROM THE BATTERY CAUSING IT TO BE DEAD. AFTER RECHARGING THE BATTERY, THE CHECK ENGINE CODES READ THAT THERE IS A PROBLEM WITH 'BRAKE LIGHT ILLUMINATION.' HELP IN DETERMINING WHA T IS CAUSING THE BATTER…
2020 GMC Sierra electrical problems
moderate 48 complaints filed with NHTSA · avg repair $850
Complaints
48
Recalls
0
Crashes
0
Avg fix
$850
What owners are reporting 4 most recent
The morning of December 12th, 2025 I used my vehicle to transport my daughter approximately 5 miles round trip from our home to drop her off at daycare and then I returned home. I used my front and rear defrost elements to expedite removal of heavy condensation which had formed on all windows overnight. This was approximately 7 AM. I parked my truck in the driveway and went inside until approximat…
AFTER HAVING ALL SORTS OF WARNINGS OVER TIME LIKE "SERVICE ESC," "SERVICE PARKING BRAKE," AND MORE, I NOW SEE "BRAKE SYSTEM FAILURE: 62 MPH TOP SPEED" FLASH ACROSS MY DASH. I AM READING AND HEARING THAT THIS IS A VERY DANGEROUS PROBLEM. NEW TRUCK. BRAND NEW. HAD IT LESS THAN A YEAR. BRAKE MESSAGE ALWAYS ON START UP.
The contact owned a 2020 GMC Sierra 1500. The contact stated that after the vehicle was purchased and while driving at an undisclosed speed, the check engine warning light illuminated. The dealer was contacted. However, the check engine light turned off, and the dealer refused to inspect the vehicle. The contact stated that while driving at an undisclosed speed, the vehicle jerked and the check en…
Common questions
How serious is the electrical problem on the 2020 GMC Sierra?
It's a documented issue but not catastrophic. 48 complaints have been filed. Repairs average $850 and most owners catch it before it causes a breakdown.
At what mileage does the electrical typically fail?
Mileage data is limited for this issue. Owners report failures across a wide range, suggesting cause is more about driving conditions and maintenance than mileage alone.
What does it cost to fix?
Independent shops typically charge around $850 for electrical repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to electrical?
No active recalls currently cover electrical issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Other problem areas on this vehicle
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Severity ratings are derived from reported crashes, fires, injuries, and fatalities.
Repair cost estimates are independent-shop national averages and may differ in your area.
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