Electrical System Problems of Chevrolet Blazer - part 2

Coolant temp gauge stuck on cold, ac quits blowing cold air, reads the thermostat code when check engine light comes on. Was told my car needs a new thermostat and a coolant temp sensor. This has proven to be a common issue among Blazers. There is no rhyme or reason when this happens and will fix itself after a while, but then happens again.

See all problems of the 2019 Chevrolet Blazer 🔎.

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.

See all problems of the 2020 Chevrolet Blazer 🔎.

I am experiencing the well known "shift to park message" while the shifter is in park. I cannot turn the vehicle off and I am worried the battery will die. This is a well documented issue with this vehicle, and several other models outlined in TSB 19-na-206, for years and yet they refuse to issue a recall to repair the faulty design or component . I have reached out to them via email, but no action has been taken, see email below. ------------------------------------------------------------------------------------- gm customer care, I am writing to request assistance regarding an issue with my 2020 chevy Blazer VIN# [xxx] . This is my fourth new gm vehicle, and while it is currently outside the 36-month warranty period, the vehicle has only 18,800 miles on it. Recently, the vehicle began displaying a persistent "shift to park" message on the driver information center, despite the gearshift being in the park position. As a result, the vehicle remains in the on position and cannot be turned off. This is a well-documented issue affecting several gm models, including the Blazer, acadia, malibu, traverse, and volt. For reference, please see TSB 19-na-206 attached. Repair costs for this issue appear to vary widely, sometimes exceeding $1,000 depending on location and dealership. Given that this appears to be a known design or component issue, I do not believe this should be an out-of-pocket expense for the customer. As a long-time gm customer, I respectfully request that gm cover the cost of this repair. I am disappointed that there has been no proactive recall or service campaign, especially considering the volume of customer complaints reported online. Thank you for your time and attention. I look forward to your response and hope gm will stand behind its products in this matter. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

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

See all problems of the 2021 Chevrolet Blazer 🔎.

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

When you put your Blazer in park you get the warning light and chime to 'shift it into park'. So far it has happened to me 5 or 6 times in the past couple days. I can jiggle the shifter handle to get the chime to stop but it has me concerned. I have seen numerous posts about this same problem.

Almost every time I start the car up it asks me if the vehicle is a demo. I will sign in as a user and identify the vehicle and keys, but it seems to lose some of the information when it is turned off. It has happened hundreds of times.

35,000 miles and p0128 code that does not resolve after expensive repairs of coolant temperature sensor and thermostat multiple times.

The glare reflecting from the dashboard on to the windshield is many times blinding and obstructs a lot of the front view. Also randomly the side mirrors tilt up while driving giving me a view of the sky but not the road behind me.

See all problems of the 2024 Chevrolet Blazer 🔎.

To whom it may concern, I am writing to formally file a complaint regarding ongoing and persistent issues with my 2020 Chevrolet Blazer. The vehicle has exhibited repeated problems that I believe may indicate a broader safety or mechanical defect, and I am requesting that the NHTSA investigate these concerns further. Since purchasing the vehicle, I have experienced the check engine light turning on and off repeatedly, without consistent resolution. The following issues have occurred over time, all seemingly related to the engine or control systems: engine cooling system failure: the first major issue involved the engine cooling system. This caused the vehicle to overheat and required service. I was concerned about the potential for engine damage or fire risk due to excessive heat. Variable valve timing (vvt) system malfunction: shortly after the cooling system issue, the vehicle began experiencing problems with the variable valve timing system. This not only affected performance and fuel efficiency but also caused the check engine light to illuminate again. Steering control assist sensor warnings: most recently, the steering control assist sensor has started to malfunction, with warnings frequently popping up on the dashboard. This has impacted steering feel and raises serious safety concerns. Despite multiple service appointments and repairs, these problems persist or reappear. This cycle of temporary fixes without a lasting resolution is both frustrating and concerning from a safety standpoint. I am requesting that the NHTSA look into whether these recurring engine and control system issues are part of a known defect or recall-worthy problem affecting the 2020 chevy Blazer. Thank you for your attention to this matter.

P0128 error, power steering reduced warning, cooling fans on, no a/c and temp gauge stuck on cold.

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

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.

To whom it may concern, I purchased a new 2020 chevy Blazer from the dealership five years ago. Since then I have had to replace my battery twice, radiator and now the thermostat all of which have been done at the dealership. The car and all receipts of the repairs are available for inspection if requested. This most recent mechanical issue with the thermostat included the following; fans blowing on high, no ac, check engine light, steering assist reduced message, and temp gauge on c. The car was immediately (same day) taken to the dealership for investigation. Upon inspecting the car the mechanic found the thermostat sticking open and indicated that it would need to be replaced as it was unsafe to drive. A total cost of $1400. It seemed odd that my car is only 5 years old with 75k miles and needing to have the thermostat replaced so I started researching this issue further. . Read more...

Coolant temperature would not read, steering assist malfunctioning, air conditioner intermittent. Wiring harness for sensors loomed together with coil pack wiring interrupting signals.

I started receiving the message “steering assist reduced, drive with care” although I’ve noticed no reduction in power steering. This has happened multiple times. The a/c stops working, the temperature gauge moves to 0 degrees and the engine fan goes to maximum speed. I have noted that this is a common issue with the Blazer.

In March 2025 a steering assist reduced warning came on briefly. Over the next several weeks intermittent. April 2025 engine warning light came on. 4-14-25 went to toddwenzel Chevrolet for diagnosis to be told the thermostat needs to be changed and due to a small amount of crystallization on the radiator that as well. I had just had oil changed and fluid levels topped off that morning at parkway express who did not identify concerns. 4-15-25 brought to parker brake who diagnosed and identified there was a glitch that prompted the warning and they can tell that fired when not driving, temp 125degrees. "it may have been parked cooling down". They noted not need for additional service. Thermostat fine and no evidence of radiator leak. They cleared codes/engine warning. After about a week experiencing intermittent assist reduced warning again. I am understanding that this is a known problem w/ these Blazers and changing thermostat for many does not work. Where does this leave me? gm needs to help with the cost and figuring this out. I am concerned about sudden failure of something while driving that could be unsafe for myself/others.

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.

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

I bought a 2019 chevy Blazer in February 2023 . The vehicle has issues when I fill it with gas. As soon as I gas up to full it starts jerking immediately afterwards. It makes loud popping sounds. The engine dies completely. It starts to tremble and will not go. When I try to turn in back on , the starter works very hard before it will turn back on. It does turn back on eventually but I have to pull over to the side and accelerate the engine until it finally stays on. I drives that way turning off at lights and stops. After about 10-15 minutes of this , it finally stays on long enough to drive another 20 minutes or so to get home. After it rests for a few hours, it goes like normal. This is a big safety concern for me since these episodes happen every week when I fill up my car with gas. I have almost been hit from behind during these episodes and it is very scary and such a hassle to have to deal with this every week. I have already had several chevy dealers and mechanics work on this problem and it continues to act up like this. I have all the paperwork for the work that has been done. $15, 000 have already been spent on this problem and the problem still continues. Please help me. I like chevy vehicles and have always bought chevy but this is the second chevy vehicle that has given me problems when I gas up. Please look into this problem. My phone number [xxx] if you need to make contact with me by phone. Thank you [xxx] [xxx] information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).

Driver steering assist reduce message in display. Upon scanning codes, error code p0128 triggered. Temperature gauge does not register on dial between c-h.

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.

Ac not working, temp gauge stuck at c, steering assist reduced happened a year ago, went away, came back. Would fix short term if battery was disconnected and reconnected or if code was cleared. Found lots of others with this same issue.

Thermostat failure. No a/c, no power steering, engine light on.

The right side tail signal light module needs to be replaced. I was having intermittent issues with the right turn signal, I took the car to the dealership and they told me that the module needed to be replaced. The car has been in the dealership since March 19th, more than a month ago waiting for the part. I contacted Chevrolet and they keep telling me that no eta for part is available, and they do not provide any more details on what is causing this delay.

Multiple safety-critical malfunctions have occurred on this vehicle involving unintended braking, unintended acceleration, and false activation of driver-assist systems. These events did not happen at the same time and occurred under normal driving conditions. At various points, the vehicle has suddenly applied the brakes without driver input, including hard braking events that felt like an automatic emergency braking activation when no hazard was present. In separate incidents, the parking brake has engaged while the vehicle was in motion, causing abrupt deceleration. There have also been instances of unintended acceleration where the vehicle surged forward briefly without additional throttle input. These malfunctions appear to be related to electrical or adas system faults affecting braking logic and propulsion control. No warning lamps or messages reliably appeared before these events. The issues pose a serious risk to the safety of the driver and others because the vehicle’s behavior is unpredictable and can interfere with safe control. The dealership was unable to reproduce the conditions during inspection, but the incidents have occurred multiple times in real-world use.

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.

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. ].

On Saturday, March 8, 2025 I was crossing a busy intersection when my car shut off completely and accelerated into oncoming traffic almost causing a collision or fatality. My brakes locked and steering wheel locked. I had to put the emergency brake on in order for the car to come to a stop. We got out of the car in the middle of the street and ran for safety. Scariest experience I’ve ever been in especially with my family in the car!!.

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.

Vehicle is available upon request. 5/28/23 tires needed replaced, not even 30,000 miles on car. Customer was charged. 6/13/23 struts and mounts replaced at dealership 3/29/24-revs high when barely touching pedal. Turned car off and it started back up on its own. Happens at least once a week. Dealership was unable to recreate. 4/1/24- wheel bearing replaced, customer was charged. April 2024 black metal showing through white paint. Paint was thin and fading. Dealership repainted the 2 doors that had paint issues. 12/20/24- antifreeze level was at bottom of reservoir. Sloshing noise when driving. Was told air in hoses and will work it's way out. Was back at dealership 1/15/25, 1/24/25 & 2/5/25. Radiator fluid still dropping but even with dye test they can't figure out where it's going. Terrified it's going to effect the water pump and engine.

When I shift the car into park and turn it off I get a message that it isn’t in park though it is as displayed on the console. To clear the message I have to move the shifter back and forward several times. I’ve had it in the shop twice already but the problem continues to return. This should be a recall!!.

This is dash warning that came on saying "action required, steering assist is reduced, drive with care" on 2021 chevy Blazer, 28. 800 miles. First happened 1/15/25 & each time car is started it is on now, plus the check engine light is on now. The fan of the motor runs for 5-10 minutes once car is shut off also. I have read of the power steering locking totally up on other Blazers that this has happened on, making this a very big danger and risky. I am not sure if it is power steering, electrical, or engine issue, but believe with so many reports out there and it causing a danger to people driving, gm/Chevrolet should put a recall on this and look at these before people are killed (if not already due to this). I am taking mine to chevy dealer to have it looked at, but many people may not have that option.

Common issue, the steering assist is reduced and temp gauge is stuck on c. This either a thermostat or temp sensor issue.