This service bulletin provides a procedure to test and replace the battery distribution fuse block if found the cause of the DTC and electric coolant pump inoperative.
full bulletin at NHTSA ↗2021 Chevrolet Blazer electrical problems
moderate 26 complaints filed with NHTSA · avg repair $850 · see electrical across all vehicles →
Complaints
26
Recalls
0
Avg fix
$850
What stands out
Owners have filed 26 electrical complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
Among the 8 model years of Chevrolet Blazer in our records for electrical problems, this one ranks #3 by owner-complaint volume.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering electrical on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This bulletin provides a procedure on how to check for a battery drain utilizing the Picoscope and how to measure the load on the system that may be causing a drain.
full bulletin at NHTSA ↗This service bulletin provides a procedure to add deadener to the batter tray bracket to correct customer concerns of a Service Engine Soon (SES), Reduced Power, Service Brake, Reduced Steering and/or Stabilitrak Message Illuminated on DIC, multiple DTCs.
full bulletin at NHTSA ↗This service bulletin provides information on the proper Reflective High Temperature Heat and/or Insulating Tape to use for certain repairs, such as Wiring Harness Repairs.
full bulletin at NHTSA ↗This service bulletin provides a repair procedure to correct a customer concern of a Malfunction Indicator Lamp (MIL) Illuminated - DTC P3055 Set.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
The 2021 Chevrolet Blazer electrical complaints cluster around several distinct, recurring problems.
The most frequent issue is an engine coolant temperature (ECT) sensor or thermostat malfunction that causes the temperature gauge to peg cold, kills the A/C, and runs the cooling fan continuously—even after shutdown. Owners report 'Steering Assist Reduced' and 'Driver Assist' warnings accompanying these failures. Dealerships have replaced ECT sensors without fixing the problem; some owners resort to diagnostic tool resets or battery disconnects, which provide temporary relief before the fault returns within days or weeks. No manufacturer recall has been issued.
Infotainment system failures are widespread and expensive. The display shows 'Update Failed. Return to Dealer' unprompted, disabling radio, GPS, navigation, safety cameras, hands-free calling, and OnStar emergency services. Dealers quote $1,500–$2,000 for complete unit replacement and deny warranty coverage on vehicles less than a year old. Owners document multiple online communities dedicated to this issue across several Chevy models using the MyLink system.
Keyless entry receiver module failures prevent the vehicle from starting or unlocking, with error messages referencing low key fob battery even after replacement. One vehicle remained at a dealership for three weeks; another experiences intermittent shutdowns while driving.
Instrument clusters black out completely at very low mileage (under 3,000 miles), eliminating speed, fuel, and tire pressure displays. One diagnostic code (U0155) corresponds to an IPC error; dealers apply software updates as a fix but do not cover the repair under warranty.
Fuel pump control module failures cause sudden engine stalls at low mileage (under 15,000 miles), including on highways at speed. One owner notes an active recall exists for the same module on similar-era Silverado and Tahoe vehicles, yet their Blazer VIN does not appear in GM's recall database.
Multiple complaints describe unrelated electrical cascades—headlights flashing, hatches opening, transmissions shifting erratically, dashboards going blank—with no diagnostic codes generated and dealerships unable to replicate or diagnose the failures.
Same Chevrolet Blazer electrical reports on nearby years: 2019 · 2020
Failure modes owners describe
Engine Coolant Temperature (ECT) Sensor / Thermostat Malfunction
Temperature gauge reads cold or stays pegged to cold; engine cooling fan runs continuously or on high speed even after engine shut-off; A/C stops functioning; 'Steering Assist Reduced' or 'Driver Assist is Stopping Drive with Caution' warnings appear. Owners report the issue occurs intermittently or repeatedly; some reset errors via diagnostic tools or battery disconnect and the problem returns within days or weeks. Dealers have replaced ECT sensors without success; online sources suggest thermostat replacement as costly alternative, though some report replacement did not resolve the issue.
When: Occurs early in vehicle ownership (6 months to under 40,000 miles); some incidents as early as 24 miles into a drive
Symptoms owners cite: Temperature gauge reads cold or pegged to cold; A/C stops working; Engine cooling fan runs continuously or on high speed; Fan continues running after engine is shut off; Steering Assist Reduced or Driver Assist warning messages; Noise from hood area
Codes mentioned: P0128, P2018
Repairs/costs cited: Owners cite ECT sensor replacement (unsuccessful in at least one case); thermostat replacement mentioned as expensive alternative but reportedly ineffective in some instances; diagnostic tool reset temporarily resolves issue
Recalls/TSBs owners mention: Dealership personnel report this is a frequent repair. Some dealers unable to duplicate issue. No recall mentioned by owners.
Infotainment System / Radio Display Failure ('Update Failed' Error)
Infotainment screen displays 'Update Failed. Return to Dealer' message; complete loss of radio, GPS, navigation, safety camera display, turn signal audio, hands-free calling, and OnStar emergency services access. Owners report the issue occurs after parking the vehicle with everything working normally, then discovering the failure the next time they attempt to use the vehicle. Multiple complaints reference dedicated online communities documenting this widespread issue across multiple Chevy model years using MyLink infotainment system. Dealers report inability to repair the unit and quote replacement of entire radio assembly.
When: Occurs unpredictably; owners report it happens overnight with no warning or user-initiated update
Symptoms owners cite: Infotainment screen displays 'Update Failed. Return to Dealer'; Complete loss of radio functionality; GPS and navigation unavailable; Safety cameras disabled; Turn signal audio eliminated; Hands-free calling inoperative; OnStar emergency services inaccessible
Repairs/costs cited: Dealers quote $1,500–$2,000 for complete radio/infotainment unit replacement plus labor; owners report dealers deny warranty coverage on vehicles less than 1 year old
Recalls/TSBs owners mention: Dealers acknowledge the issue occurs but claim no warranty coverage; owners note GM/Chevy appears aware of defect in MyLink system but refuses to address it as recall
Fuel Pump Control Module Failure
Engine stalls without warning while vehicle is running or immediately after startup. At least one owner reported the failure occurred in a parking lot; another on a highway at 60+ mph, forcing the vehicle to coast across three lanes of traffic. Owners note no check engine light prior to failure, only after the stall. One complaint references a known recall for the same module on Silverado and Tahoe vehicles from the same manufacturing era; owner's VIN does not appear in the active recall database despite having the identical vehicle and model year.
When: Occurs at low mileage (4,954 miles to 14,000 miles); one complaint at unknown mileage
Symptoms owners cite: Engine stalls while driving; Engine stalls immediately after cranking; Vehicle unable to restart immediately; Slight shuttering before stall; No warning indicators prior to failure
Repairs/costs cited: One owner reports the dealership identified a faulty fuel pump and installed an updated replacement module
Recalls/TSBs owners mention: Recall exists for fuel pump control module on Silverado and Tahoe; owner reports their 2021 Blazer VIN does not appear in GM recall database despite identical module issue
Keyless Entry / Key Fob Receiver Module Failure
Vehicle will not start; doors will not lock or unlock. Dashboard displays error message indicating key fob battery is low even after battery replacement in a second, unused fob. Issue is not a faulty key fob but a failure of the receiver module that processes the fob signal. Vehicle immobilized and required towing to dealership where it remained for over 3 weeks during diagnosis. Another complaint describes intermittent 'No Remote Detected' error messages appearing and disappearing; vehicle periodically shuts down while in drive or reverse without warning.
When: Occurs early in vehicle ownership (6,000 miles or less); one incident after 3 months of ownership with 25,000+ miles
Symptoms owners cite: Dashboard displays 'No Remote Detected' or 'Low Battery' error messages; Vehicle will not start; Doors will not lock or unlock via fob; Error messages intermittent; appear on multiple key fobs; Vehicle shuts down without warning while in drive or reverse
Repairs/costs cited: Dealership tow required; extended service duration (3+ weeks); OnStar attempted remote diagnostics without success; dealership provided rental vehicle under warranty
Recalls/TSBs owners mention: Vehicle under 1-year-old warranty at time of failure; GM provided rental vehicle; no mention of recall
Instrument Cluster / Digital Display Blackout
Digital instrument cluster goes completely black, displaying no vehicle speed, engine status, fuel level, tire pressure, or other critical information. Occurs at very low mileage (1,200–2,700 miles). In one case, blackout also disabled steering wheel radio controls and deactivated lane-assist safety feature. Another complaint describes instrument cluster going blank intermittently for several seconds before rebooting, repeating this cycle and preventing driver from seeing speedometer or turn signal status.
When: Occurs very early in ownership (1,200–2,700 miles); one complaint references 50,000 miles
Symptoms owners cite: Instrument cluster display completely black; No speed indication; No engine status information; No fuel level display; No tire pressure warning capability; Steering wheel controls inoperative; Lane-assist feature disabled; Intermittent cluster reboot cycle
Codes mentioned: U0155
Repairs/costs cited: Chevrolet dealer diagnosed as IPC (Instrument Panel Cluster) error U0155; updated software installed; owner reports not covered by extended GM warranty purchased at time of sale
Recalls/TSBs owners mention: Software update applied as repair; service bulletin exists covering multiple GM models; owners indicate this should be recall-level defect
Brake System Failure / Low Voltage Condition
Brake pedal becomes unresponsive while driving; vehicle loses braking ability. Dashboard displays 'Brake System Failure' error message. Dealership attributed failure to low battery voltage and refused to operate the vehicle until battery was replaced. No warning messages appeared prior to the failure event.
When: Unknown mileage; occurred while driving
Symptoms owners cite: Brakes unresponsive while driving; Complete loss of braking ability; Brake system failure warning message appears at time of failure
Repairs/costs cited: Dealership diagnosed low battery voltage as cause; required battery replacement before vehicle could be operated
Recalls/TSBs owners mention: None documented; owner believes this constitutes a manufacturing defect requiring recall
Multiple Electrical System Failures and Unexplained Warning Lights
Assorted unrelated electrical failures occurring simultaneously or in clusters: headlights flashing or staying on in low or high beam; rear hatch opening itself; AWD making popping noise and shifting into AWD mode by itself; transmission not shifting correctly; noise in dashboard; steering wheel controls malfunctioning; multiple warning lights illuminating and flashing on/off; entire dash going blank momentarily before rebooting. No diagnostic trouble codes are thrown despite multiple failures. One complaint notes keyless entry pad malfunctioned the day of purchase and was replaced; electrical problems began afterward. Another describes failing to restart, with code reader indicating fuel pump control module despite the module being under recall.
When: Occurs at low mileage (reported ranges 2,700–50,000 miles); some within first week of ownership
Symptoms owners cite: Headlights flashing or stuck on (low or high beam); Rear hatch opening by itself; AWD making popping noise; AWD shifting into gear by itself; Transmission shifting erratically; Dashboard noise; Steering wheel controls inoperative; Multiple warning lights illuminating and flashing; Entire dashboard going blank momentarily; No codes generated despite multiple failures
Repairs/costs cited: Dealerships unable to recreate failures or provide diagnosis; no parts replacement documented in complaints
Recalls/TSBs owners mention: Manufacturer notified in at least one case; callback promised but not received
Vehicle Stalling / Shutdown While Driving
Engine shuts off unexpectedly while vehicle is in motion at various speeds, from city streets to highway speeds above 60 mph. In one case, '2 Keys Detected' message flashed on dashboard immediately prior to shutdown. Another complaint describes slight engine shuttering before shutdown on highway. Vehicle either will not restart immediately or takes 15 minutes to restart. Owners report no check engine light prior to shutdown in at least two cases.
When: Occurs at varying mileage and times; one incident at 2 days after purchase, another with no mileage specified, one at highway speeds
Symptoms owners cite: Engine shuts off without warning while driving; Slight engine shuttering before shutdown; Dashboard error messages ('2 Keys Detected') appearing before shutdown; Vehicle difficult or slow to restart; No check engine light prior to event
Repairs/costs cited: Dealerships unable to recreate or identify cause; fuel pump control module identified in one case
Recalls/TSBs owners mention: None documented
Synthesized from 26 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 5 most recent
"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.
Upon driving my vehicle twice it shut off on the roadway once on an incline when a message of 2 keys detected and flashed on the dashboard prior to the vehicle shutting off. Vehicle would not restart until 15 minutes later it restarted but the dashboard kept flashing 2 keys detected. There was only one key in the vehicle at the time and the key fob has had the battery replaced upon the first…
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…
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,…
See attached document for complaint.
Had electrical trouble with your 2021 Chevrolet Blazer?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the electrical problem on the 2021 Chevrolet Blazer?
It's a documented issue but not catastrophic. 26 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?
Based on the 26 complaints filed, electrical issues most often appear around 30,233 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
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.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Chevrolet/Blazer.
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. Some links on this page are affiliate links.