Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2020 Chevrolet Blazer owners, lightly cleaned up (personal details are redacted by NHTSA).
My 2020 Chevrolet Blazer experienced severe mechanical problems, including stuttering, loss of power, and the engine shutting off unexpectedly while I was driving. The vehicle subsequently would not operate normally. On February 25, 2026, Rick Hendrick Chevrolet Duluth performed a diagnostic inspection and recommended nearly $20,000 in repairs, including transmission-related repairs. However, the dealership did not identify or disclose any alternator fire damage or related electrical safety concerns. In October 2026, an independent mechanic discovered significant burn damage on the alternator. The damage was visible externally, and further inspection of the alternator's interior revealed additional evidence of burning. I believe this condition may have contributed to the vehicle's sudden loss of power and shutdown. …
The contact owns a 2020 Chevrolet Blazer. The contact stated that while parking the vehicle and shifting to park(P), the message "Shift to Park" was displayed. The contact turned off and restarted the vehicle several times and shifted from drive(D) to park(P) several times before the message disappeared. The contact stated that the vehicle was also showing electrical failures. The contact stated that after shifting to park(P) and turning off the vehicle, the contact heard chimes as if the vehicle was still running. There was no warning light illuminated. The contact stated that one morning the vehicle had to be jumpstarted and on another morning the battery was completely drained. The battery was taken to an Auto Parts Store to be checked. The contact was informed that the battery was in good operating condition. The contact stated that the battery was drained again and was replaced. …
The contact owns a 2020 Chevrolet Blazer. The contact stated while driving approximately 45 MPH, the instrument cluster went black, and the vehicle stalled. The contact stated that there was no warning light illuminated or an audible chime heard. The contact stated that several attempts were needed to restart the vehicle. The vehicle was restarted, and the message "Vehicle in Transport Mode" was displayed. The contact stated that the failure was intermittent but reoccurred. The contact stated that the vehicle was not taken to a dealer or independent mechanic to be diagnosed or repaired. The manufacturer was informed of the failure and referred the contact to the NHTSA Hotline for assistance. The failure mileage was approximately 92,000.
The contact owns a 2020 Chevrolet Blazer. The contact stated that the front passenger's seat belt buckle was inoperable. The contact buckle was jammed and failed to properly secure the seat belt in place. The contact stated that while driving and stopped at a red light, the traffic light turned green and the accelerator pedal was depressed; however, the vehicle surged forward unexpectedly while rolling. Additionally, the contact stated that the infotainment system intermittently displayed a blank or distorted screen, became frozen and was unresponsive to the touch commands. The vehicle was not diagnosed or repaired. The manufacturer was not notified of the failures. The approximate failure mileage was 75,000.
The contact owns a 2020 Chevrolet Blazer. The contact stated that while driving approximately 70 MPH, the message, "Steering Assist Reduced - Drive Carefully" was displayed. The contact stated that the A/C shut off and the windshield defroster failed after the message was displayed. The vehicle was taken to the dealer, and the contact was informed that the repair was not covered. The manufacturer was informed of the failure and confirmed that the vehicle was not included in the "Special Coverage" for the repair. The contact was referred to the NHTSA Hotline to report the failure. The failure mileage was approximately 65,000.
The contact owns a 2020 Chevrolet Blazer. The contact stated upon shifting to park(P) and attempting to turn off the vehicle, the message that the transmission was not in park(P) was displayed. The contact stated that the failure recurred several times, and the vehicle responded as needed after several attempts. The dealer was not notified of the failure. The vehicle was not diagnosed or repaired. The manufacturer was notified of the failure, but no assistance was provided. The failure mileage was approximately 38,000.
On multiple occasions, my 2020 Chevrolet Blazer RS has failed to recognize when it is shifted into the "Park" gear. When this occurs, a "Shift to Park" message appears on the dashboard, and the vehicle's electronics will not shut down, preventing me from turning off and locking the vehicle. This defect presents several critical safety hazards: Inability to Secure Vehicle: The engine/electronics remain active, preventing the vehicle from being turned off and secured. This could drain the battery, leaving me stranded, or make the vehicle a target for theft. Driver Distraction: The warning message has appeared randomly while the vehicle is in motion, creating a serious and unexpected distraction for the driver. …
2020 Chevy Blazer RS 3.6L V6: having intermittent issues with 'check engine' light activating and giving code P0128 - indicating "Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)". Symptoms include: - Temp gauge drops to reading "C" (cold), - AC blows warm/hot air, - Dash displays message, "Steering Assist is Reduced, Drive with Care", - Radiator (electric) fans run full speed. It seems that the computer is interpreting the engine coolant temperature sensor drop as a 'stuck open' thermostat, thus the indicated code. However, at the same time it also appears to assume a bad coolant temp sensor, and failsafes to disable the AC and set the radiator fans to max to avoid potential overheating. …
The vehicle experiences a constant cooling system failure that appears to be related to the thermostat. Beginning at approximately 40,000 miles, the engine cooling fan started running continuously at high speed whenever the vehicle is operating. At the same time, the air conditioning stopped functioning properly and the vehicle began displaying a warning message indicating that steering assist is unavailable or reduced. The vehicle is available for inspection upon request. This condition creates a safety concern because the steering assist warning indicates a potential reduction or loss of power steering assistance, which could increase steering effort and make the vehicle more difficult to control, particularly during low-speed maneuvers or emergency situations. The warning appears during normal vehicle operation and can distract the driver. …
I am contacting you regarding my 2020 Chevy Blazer with approx $55,580 Miles. the vehicle is experiencing multiple issues consistent with the know thermostat problem reported on many 2020 Blazer, including the P0128 code, cooling fans running at high speed and "steering Assist Reduced" warnings. The Steering wheel has now become hard to turn while driving, creating a serious safety concern for me and my family, I m [redacted] old and yesterday in mother's day) while I was driving on the expressway with my grandchildren in the vehicle, the steering suddenly became very had to turn and I was almost involved in an accident, This situation was extremely alarming and poses a significant safety risk. …
Electrical complaints in other Blazer years
Frequently asked questions
How common are electrical problems on the 2020 Chevrolet Blazer?
NHTSA has 77 complaints about the electrical system of the 2020 Chevrolet Blazer, 35% of the model year's 222 complaints.
Is there a recall for 2020 Chevrolet Blazer electrical problems?
No. NHTSA lists no electrical system recall for the 2020 Chevrolet Blazer, though it has 3 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2020 Chevrolet Blazer electrical problems start?
Half of the complaints with a recorded mileage happened before about 38,000 miles, and 44% before 25,000 miles.
Is it dangerous?
Owners linked 0 crashes, 1 fire and 0 injuries to electrical system problems on this model year. If you notice symptoms, have the car checked before driving further.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.