Electrical System Problems of Chevrolet Blazer - part 1

Thermostat not working. Causing fan to run as if the vehicle is overheating.

See all problems of the 2023 Chevrolet Blazer 🔎.

1. Fuse array has failed, and yes it is available for inspection upon request 2. The car overheats, posing a threat to passengers lives due to having to pull over on the side of the road and being struck by other drivers. 3. Yes it has been confirmed by a dealer/service center. 4. Yes it has been inspected by certified service technicians. 5. Yes, the engine light comes on and the dash says “engine power reduced” and then “vehicle overheating, please pull off the side of the road and turn engine off”. There were no symptoms leading up to the vehicle overheating. This first occurred in April 2025, and occurred again September 6, 2025. When speaking to the dealership, they stated that this is a widespread issue with Chevrolet Blazers and because of how big this issue is, new parts are on back order until middle to end of October. I cannot drive the vehicle to go grocery shopping or bring my daughter to daycare. Because this is a widespread problem, there needs to be a recall issued. Chevrolet installed faulty fuse arrays in their vehicles and this is their fault for this happening at such a large scale.

See all problems of the 2022 Chevrolet Blazer 🔎.

Shift to park warning comes on when car is in park, car electrical will not shut off until the shifter is shaken or car is turned back on and shifted into gear and back to park, may take several times.

See all problems of the 2020 Chevrolet Blazer 🔎.

This is a report of defective software that could increase the chances of an accident, injury and or death. This vehicle features a built-in garage door remote which is utilized exclusively through the touch screen. However, when the vehicle is in reverse the backup cameras restrict access to the needed menu. After backing up and putting the car in drive there is a delay before the back up camera turns off. This creates a situation in which the driver must wait in the middle of the road after placing the car in drive before being able to close the garage door. In seeking solutions from online forums, some drivers have reported their Blazer evs allow the button to be accessed while others report they do not, so I speculated perhaps I missed a software update, but per the car's ota system, the vehicle's software is current as of the time of this submission. I have recorded a video that I am happy to share , however it exceeds the size limit allowed for uploads in this report.

1. The vehicle does not recognize it's in park periodically and will not shut off 2. Thermostat housing and thermostat failure 3. Tint covered chrome on exterior of body peeling off only had the car 3 weeks currently at dealership repairing thermostat out of pocket.

See all problems of the 2019 Chevrolet Blazer 🔎.

I am currently receiving a shift to park message displayed while my vehicle has been put in park and after I turn the vehicle off. While the message is displayed, the doors will not lock and a bell will not stop dinging, notifying me of the error. I have to start the vehicle, shift into gear, shift into park, and turn off several times before the error disappears. I have an appointment to have the dealer look at it this week.

The well known shift to park issue where the park sensor is off and my vehicle won’t shut off without being able to register it’s in park. Auto garage quoted $600+ to replace the entire shift assembly. There’s a service bulletin out for this issue and the specific 2019 Blazer but no recall.

While driving the vehicle loses power to the instrument panel and gauges and infotainment system. The vehicle remains under power however the driver looses the ability to see how fast the vehicle is moving or any information as the entire dashboard loses power. The safety to both myself and my family as well as other drivers is at risk if I am unable to see how fast I am going or control any equipment in my vehicle. This is a known issue online with many other drivers of the Blazer ev experiencing the same issue with no remedy from the manufacturer.

See all problems of the 2024 Chevrolet Blazer 🔎.

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.

See all problems of the 2021 Chevrolet Blazer 🔎.

After getting the recall repaired (which I was never informed of and I had the parking brake engage as I was travelling 30 mph causing me to skid down the road) I got the vehicle back and the very next day it was the same issue and the abs and traction control light came on and it began making loud clicking noises every time I would engage the brake.

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 had not taken the vehicle to a local 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 40,000.

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.

Vehicle gear shifter is stiff and difficult to pass from park to drive--the gear shifter gets stuck in neutral often. The entire dash and instrument cluster goes black during driving and will not come back on until hours later even after the vehicle has been turned off and back on. This has caused me to be unable to see my speed, turn signals, fuel gauges or any engine controls. This leaves me unable to operate or control my vehicle. This is a huge safety issue when driving as I am unable to determine my speed or see any of my vehicles controls or warnings. The front passenger seat motor has a horrible vibration and struggles to adjust the seat properly. I have contacted multiple dealerships on multiple occasions regarding these issues and have been told that the extended warranty will not cover any of these issues although I was told it would when I purchased. Chevy has refused to offer assistance with towing the vehicle to a dealership when the cluster stops working and encourages me to drive a vehicle that is not operational. The service manager at one location told me this was a known issue with the vehicle.

At startup, I would receive a message that said, steering assist reduced. There were no check engine lights or warning lights. My air conditioning stopped working, and my temperature gauge on the dash remained at cold. I also noticed the radiator fans were on full blast, continuously. I called the dealer, and they weren't sure what was causing that. I told them I was getting codes #u0401 & p0128. They asked me to clear the codes to see if they returned. I cleared the codes, but they returned immediately on restart of the engine. I'm going to replace the thermostat but I didn't understand the #u0401 code, so did further research. I found 2017 bulletin #17-na-158 which seamed relevent to my issues, and vehicle fitment that confirmed my 2019 chevy Blazer is included. I then came to find that the un-shielded low voltage wires for the coolant temperature sensor are routed through the same harness as high voltage coil wiring. Some of us know that emi will affect low voltage signals. As an hvac system designer, I know that un-shielded low voltage communication wiring cannot run parallel two line voltage power wiring. The effects are not continuous, but definitely reoccurring. I also understand there has not been a recall for this issue which surprises me. I can replace the thermostat even in its difficult position, but I don't feel comfortable in separating the low voltage wiring from the harness. I understand that dealers who are aware of this issue, charge a hefty fee to do so. It's definitely one that I can't afford.

Shift to park message began appearing even after the shifter knob was in park. I cannot turn the vehicle off and it rolled backwards due to the vehicle not recognizing it was in park. This has now cost $700 to repair when its been a known issue with these vehicles for over 6 years and yet they refuse to issue a recall. This is dangerous and disgusting practice for a vehicle manufacturer to avoid keeping their customers safe.

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.

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.

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.

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.

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.