2021 Chevrolet Blazer Electrical Problems

The thermometer and thermometer sensor are glitching . The engine temp needle will not rise at all, the engine fan will run the whole time driving and then when it is turned off will run for 10 min . Right before this happens a notice shows the guided steering is being limited. I disconnected the battery and it reset , I drove and there were no issues , next time I started my car the engine temp needle stayed down and the van started again. This car has 36k miles on it. I just bought it 2 days before it started happening

NHTSA ID

11745573

Incident

Jun 21, 2026

Lost coolant temp so replaced sensor with one from auto zone and worked for one then pegged to cold again fan runs 100% so went and bought another coolant temp sensor from Chevrolet installed that worked two pegged back to cold again fan 100% now going to pay $700.00 dollars to remove the two sensor wires for the harness all the two the Ecm heard with it being wrapped in the coil wires it gets electromagnetic static due to degradation of wires. Also Radiator started leaking after couple years but they want $3100.00 dollars for that.Was told extended warranty ran out three days before they discovered radiator leak.

NHTSA ID

11742425

Incident

May 6, 2026

Once I turn the vehicle off, there is a loud sound coming from the engine area that sounds like a fan. Then the first incident of the fan ongoing after the vehicle was powered off, a battery light was on the internal driver dashboard and stayed on. The battery was recently replaced during 2026 so the battery should not be anywhere near dead, dying, or needing to be checked

NHTSA ID

11730609

Incident

Apr 11, 2026

The contact owns a 2021 Chevrolet Blazer. The contact stated that while attempting to start the vehicle, several unknown warning lights illuminated, and other lights inside the vehicle flashed on and off. The contact stated that the failure also occurred while driving at various speeds. A dealer was contacted. The vehicle was taken to several dealers for diagnostic tests; however, the diagnostic result was unknown. The manufacturer was notified of the failure and informed the contact that there would be a callback about the cause of the failure; however, there has been no callback yet. The approximate failure mileage was 50,000.

NHTSA ID

11726942

Incident

Aug 15, 2025

Mileage

50,000 mi

This submission is an additional report related to NHTSA complaint #11714381. At approximately 55,000 miles, my 2021 Chevrolet Blazer experienced a sudden throttle body failure while driving. The vehicle entered reduced engine power/limp mode without warning and acceleration was significantly limited. This created a safety concern while driving in traffic, particularly when merging and crossing intersections. Diagnostic code P2101 (Throttle Actuator Position Performance) was present. A Chevrolet dealer confirmed an internal throttle body failure and replaced the throttle body assembly. Although the repair was completed, this failure occurred at relatively low mileage for a critical engine control component. A sudden loss of acceleration can pose a safety risk depending on traffic conditions. Since filing my original complaint, I have identified multiple similar reports online and in owner forums describing premature throttle body failures in GM vehicles with similar symptoms (reduced power/limp mode and limited acceleration). This suggests the possibility of a broader pattern involving this component. I am submitting this additional report so that NHTSA has a complete record of the incident and potential pattern of premature throttle body failures. If this issue is widespread, it may warrant further review or investigation as it affects vehicle acceleration and safe operation.

NHTSA ID

11719088

Incident

Jan 7, 2026

Around 55,000 miles, my 2021 Chevrolet Blazer experienced a throttle body failure. The check engine light illuminated and the vehicle entered a reduced power/limp mode condition. Throttle response was significantly limited, and the vehicle could not accelerate normally. While the vehicle remained drivable, it took substantially longer to reach speed, which could pose a safety risk when merging into traffic or crossing intersections. Diagnostic trouble code P2101 (Throttle Actuator Position Performance) was present. A Chevrolet dealer confirmed an internal throttle body failure and replaced the throttle body assembly. This component is a critical engine control system, and failure could affect acceleration and vehicle control, posing a potential safety risk. The failure occurred well before expected service life and required a costly repair. The component has been replaced and is available for inspection upon request. I believe this may represent a premature defect and should be investigated for similar failures in other vehicles.?

NHTSA ID

11714381

Incident

Jan 7, 2026

"Steering assist reduced" message was displayed. At the same time the temperature gauge stopped working and after I shut the car off, the motor fan ran full force for 10+ minutes. Shows no check engine light.

NHTSA ID

11703920

Incident

Dec 3, 2025

Car was running fine yesterday, today does not want to start. Thought it was the battery, bought anew battery. Still wouldn't start. Rest of cat is getting great power. Code reader is reading its a fuel pump control moduler which just so happens to be in an open recall for my exact year of vehicle yet my vin number does not pop up on the GMC website under active recall. I have a 2021 chevy blazer .

NHTSA ID

11699684

Incident

Nov 16, 2025

Action Required "Steering Assist Warning" drive with caution, Temp gage reads cold, A/C stops working, engine cooling fan runs on high speed (even after the engine is shut off), pending P2018 code, with no Check Engine Light (CEL). Replaced Engine coolant Temperature (ECT) sensor, problem did not go away. Several reviews suggest to replace the thermostat, check fuses for proper insertion, reroute ECT wiring, and possibly replace radiator. Most of these repairs can be very expensive. Chevy Blazer Forum states that the issue is a out of range detection of ECT sensor reading. GM needs to determine a true solution and stop guessing at owner expense/frustration.

NHTSA ID

11697313

Incident

Sep 18, 2025

See attached document for complaint.

NHTSA ID

11696400

Incident

Oct 14, 2025

In March after a short drive, 24 miles, the car temp was pegged at Cold. After turning off the car, the fan continued to run several minutes. After a quick internet search several posts commented on a similar issue with their vehicle. Two potential issues were identified - thermostat failure or programming issue. With less than 40,000 miles on the car, I purchased a diagnostic tool. Running the tool program two errors were identified. After resetting the sensors, the problem went away. In September, yesterday and today the problem occurred again - and the error reset fixes the issue. I believe Chevy needs to fix the issue with a recall to either update programming or replace the thermostat. [Several posts state the thermostat replacement didn't fix the issue and is very expensive.]

NHTSA ID

11693729

Incident

Mar 15, 2025

Odometer Fraud. The contact purchased a 2021 Chevrolet Blazer. It was discovered that there was a mileage discrepancy. The vehicle was a dealer sale. At the time of purchase, the vehicle mileage was 9,967, and at the time of registration, it was discovered that the mileage was approximately 38,000.

NHTSA ID

11693294

Incident

Apr 14, 2022

Mileage

38,000 mi

Request for Recall Review – 2021 Chevrolet Blazer Steering Assist and Cooling Fan Issue Hello, I am writing to report a recurring issue with my 2021 Chevrolet Blazer and to request that this concern be reviewed for possible recall or warranty coverage. The vehicle frequently displays an “Action Required: Steering Assist is Reduced. Drive with Care” message while driving. Additionally, after shutting off the vehicle, the engine cooling fan continues to run for up to 20 minutes, as if the vehicle is overheating. This issue has occurred multiple times and raises concerns about potential problems with the steering assist system, cooling system, or electrical sensors. I’ve noticed that other Blazer owners have reported similar experiences online, which suggests this could be a broader issue. Could you please confirm whether there are any existing recalls, technical service bulletins (TSBs), or warranty programs addressing this condition? I would also appreciate guidance on the next steps for inspection or documentation. Vehicle Information: Year/Model: 2021 Chevrolet Blazer

NHTSA ID

11692416

Incident

Sep 30, 2025

The vehicle has 14,000 miles on it and the fuel pump control module has gone out on it. This happened while away from home and could’ve caused a serious situation if this had happened in a remote area where customer could’ve been stranded or if customer were pulling onto a busy road. Luckily it happened in the parking lot of a store. The vehicle was running fine on the way to the store. When customer came back out to the vehicle it cranked up but then stalled which also left customer in between parking rows, potentially causing an accident. I have the old fuel pump control module readily available for inspection. Customer had an updated version that replaced the original one that was in it. There were no signs or indications that this was going to happen until it did. I know there was a big issue / recall with the modules on Silverado and Tahoe’s etc. around the same manufacturing era. For reference- 1/2 tank of fuel, no CEL until after it happened, approx. 88° outside, coolant temp near 120°, vehicle battery had good voltage and battery cells are good

NHTSA ID

11675095

Incident

Jul 18, 2025

On the way to work my car said “driver assist is stopping drive with care” about 2-3 times. Upon getting out of my car it sounded like my car was still running. I turned it off and on a few times and it still sounded that way. I had to go inside or I would be late so about 20 minutes later I was able to come back and check on it and the noise stopped. It was coming from the hood. Upon googling I figured it was something to do with a faulty temperature gauge which correlated with the signal from the car as well as the sounds. It seemed like this is a very common occurrence for these cars. I called the dealership and they said they fix these everyday and the man knew exactly what was wrong before I could even finish describing it. Unfortunately I don’t know the cost of this and have already had several other things to repair in my home recently so this will be detrimental to my finances if this isn’t covered. On the way home it did it again along with no AC in the 90 degree heat and then the engine light came on. We had to open the hood and leave the garage door open to prevent any possible harm that may do in the garage. This could be very dangerous for me as I drive my car everyday to work and can’t afford to rent a car for several weeks while this one isn’t working. And I’ve only had it for 6 months. Now my husband and I have ti figure out how we are each getting to work with one car until we get this fixed or we borrow a family members car.

NHTSA ID

11667243

Incident

Jun 16, 2025

The temperature sensor fails randomly. I can reset it by unplugging the battery but it will just drop off again in a week or two.

NHTSA ID

11663165

Incident

May 27, 2025

Temp stuck on cold, ac doesn’t work and driving assistance off. Fan runs after shutting engine off.

NHTSA ID

11662995

Incident

May 23, 2025

The thermostat and the sensor for the thermostat continues to go bad

NHTSA ID

11660396

Incident

Apr 10, 2025

The temp gage stays on cool. Ac does not work and the radiator fan stays on after car shuts off. Dealership finds nothing wrong.

NHTSA ID

11658808

Incident

May 4, 2025

The steering assist stopped working. The defrost stopped working because the ac stopped working. The temp gauge stopped working. Error code P0128. I have since found out all this is caused by a faulty temp sensor.

NHTSA ID

11658646

Incident

May 2, 2025

The vehicle’s brakes failed while I was driving. I was luckily able to steer the vehicle off the road narrowly avoiding hitting another car. We had the vehicle towed to a Chevy dealer and they told us the fault was due to a low voltage battery. They would also not drive the vehicle until the battery was replaced because it was giving an error message of “brake system failure”. The dealer is the only place that has inspected the vehicle at this time. The warning messages appeared at the time of failure and not before. I find this to be a manufacturing defect in need of a recall as this could have easily caused harm or loss of life.

NHTSA ID

11655932

Incident

Apr 11, 2025

The contact owns a 2021 Chevrolet Blazer. The contact stated while driving 35 MPH, the ambient air temperature was stuck on negative forty. The contact replaced the sensor. The vehicle went into ICE/SNOW Mode on several occasions and was not driving as designed. The air conditioner was blowing out hot air. Additionally, the vehicle was pulling to the right while driving. There were no warning lights illuminated. The vehicle was taken to an independent mechanic who scanned the vehicle and determined that the sensor was operating as designed. The mechanic informed the contact that there was a loss of communication. The vehicle was taken to the local dealer, where it was diagnosed that the control arm needed to be replaced. The vehicle was repaired, but the failure recurred. The dealer informed the contact that there was no recall coverage on the vehicle. The manufacturer was contacted and referred the contact to the NHTSA Hotline. The failure mileage was approximately 34,980.

NHTSA ID

11653720

Incident

Mar 29, 2025

Mileage

34,980 mi

Driver steering assist reduce message in display. Upon scanning codes, error code P0128 triggered. Temperature gauge does not register on dial between C-H.

NHTSA ID

11651786

Incident

Mar 30, 2025

I got home from work, locked my car up for the night with everything working perfectly fine, then came out to leave for work the next morning to find “update failed. Return to dealer” on the infotainment screen. I did some pretty extensive research trying to find the fix, only to find that many people are having this exact same issue in the same circumstances where their vehicle was fine when it was parked, they go to get back in and nothing with the infotainment works. According to my online research, GM/Chevy is charging anywhere from $1500-2000 to fix. I contacted few different dealers to see if I would get the same price and I absolutely did. They said, “your car is no longer covered under any warranties so you will be fully responsible for the cost of the fix.” I have no sound, no GPS on my screen so now I have to use my phone for work navigation (talk about a safety hazard), my turn signal sounds don’t work, my talk to text doesn’t work, no more hands free calls. This is a huge safety issue and makes me wonder why there isn’t a recall yet. This is not normal wear and tear. This is a glitch in the GM programming that they should take responsibility for and fix before they lose a lot of business.

NHTSA ID

11650964

Incident

Feb 24, 2025

I just got off work, and when I start my vehicle, my infotainment screen that I use for GPS and other features that are included in the safety of the car, and the screen just says, “Update Failed, Return to Dealer.”. The service advisor at Chevy says that this happens and that there is nothing they can do besides replace the entire radio, at a cost of $2000 with Labor. I also researched the issue online and there are dedicated websites to this very issue with multiple year and models in the Chevy lineup that uses the Chevy MyLink infotainment center. Which is in every vehicle they sell. So currently I’m unable to access any radio, GPS, safety cameras around the vehicle, or any of my OnStat Emergency Services that come with the vehicle due to an update that I never asked for, or even attempted to install. And for Chevy to not replace the radio but instead recognize it’s a problem but still charging you to fix something that they know is defective.

NHTSA ID

11649907

Incident

Mar 17, 2025