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 ↗2020 Chevrolet Blazer electrical problems
moderate 32 complaints filed with NHTSA · avg repair $850 · see electrical across all vehicles →
Complaints
32
Recalls
0
Avg fix
$850
What stands out
Owners have filed 32 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 #2 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 2020 Chevrolet Blazer shows a pattern of electrical and sensor failures that owners describe as pervasive and unresolved. The most common complaint centers on the engine coolant temperature sensor or thermostat sticking open: the temperature gauge gets stuck on cold, the AC blows hot air only, the cooling fan runs constantly, and a "steering assist reduced" warning appears. Owners document this happening at various mileage points and even under warranty, with some cases showing the problem recurring within two weeks of repair. Diagnostic code P01F0 is documented, and repairs averaging $600+ involve thermostat or sensor replacement.
The shift-to-park detection failure is the second major issue. The vehicle sits in park but won't turn off, draining the battery completely. Owners report jiggling the shifter or shifting back into drive and park again gets temporary relief. Service Bulletin 19-NA-206 exists, yet NHTSA has not issued a recall for the 2020 model despite recalls existing for other GM vehicles with the same defect, and repair costs run near $300–$700.
Other electrical issues reported include instrument cluster dropout (going black while driving and stalling), TPMS sensors giving false alarms and dropping off the display, multiple warning lights firing simultaneously (ESC, AWD disable, lane assist), and one rearview camera overheating to burning-hazard temperatures. An ABS control module failure was identified as a "known issue" but the dealership refused to repair it, handing the unsafe vehicle back to the owner.
Same Chevrolet Blazer electrical reports on nearby years: 2019 · 2021
Failure modes owners describe
Engine Coolant Temperature Sensor / Thermostat System Failure
Temperature gauge stuck on cold, AC blowing hot air, engine fan running continuously, steering assist reduced warnings, and loss of proper cooling system function. Often caused by stuck-open thermostat or faulty ECT sensor. Check engine light (P01F0 code documented) illuminates due to coolant temperature reading below normal operating range.
When: Variable onset; one case at 300 miles (under warranty), others at higher mileage. One owner reported first occurrence couple months after purchase (May 2023).
Symptoms owners cite: Temperature gauge pegged on cold or stuck at C; AC blows hot air only; Continuous engine fan operation even at cold starts; Check engine light illumination; Steering assist reduced warning message; Poor fuel economy; Engine overheating
Codes mentioned: P01F0, P0128
Repairs/costs cited: Thermostat replacement ($600+ documented at GM dealership); ECT sensor replacement; one owner reported $100 part requiring radiator work with injector/intake removal. Issue often recurs within two weeks of repair.
Recalls/TSBs owners mention: GM Service Bulletin referenced but no recall issued. Multiple complaints note this is a known issue affecting many 2020 model year vehicles, yet some VINs are excluded from recalls. GM refused coverage on at least one warranty claim citing rodent damage to wiring harness instead.
Shift to Park Detection Failure
Vehicle fails to recognize shifter is in park position, preventing engine shutdown and allowing vehicle to roll. Shift control module or shifter assembly sensor malfunction. Vehicle remains running with accessories powered even when shifter is positioned in park.
When: Various mileage points; one case at approximately 92,000 miles. Onset can be intermittent or frequent.
Symptoms owners cite: Shift to Park warning message displays despite shifter in park; Vehicle will not turn off; Engine continues running; Vehicle rolls backward when parked; Temporary relief from jiggling shifter or shifting through gears; Battery drain from continuous operation
Repairs/costs cited: Shift control module replacement ($300 documented); shifter assembly replacement documented; clearing OTC codes performed. Issue recurs after repair in some cases.
Recalls/TSBs owners mention: GM Service Bulletin No. 19-NA-206 issued but no recall by NHTSA. Multiple owners report this is a known issue across several GM vehicles with open recalls, yet 2020 Blazer excluded. Owners report multiple lawsuits filed. Manufacturer makes owners pay for repairs.
Instrument Cluster / Electrical System Dropout
Instrument cluster goes completely black, vehicle stalls without warning lights or audible alerts. Vehicle displays 'Vehicle in Transport Mode' message after restart. Intermittent electrical loss affecting dashboard and engine management.
When: At 92,000 miles documented; intermittent recurrence pattern noted.
Symptoms owners cite: Instrument cluster illumination loss (goes black); Vehicle stalling while driving; No warning lights before failure; Multiple restart attempts required; Vehicle in Transport Mode message display; Intermittent reoccurrence
Repairs/costs cited: Not repaired; owner did not take vehicle to dealer or mechanic for diagnosis.
Recalls/TSBs owners mention: Manufacturer referred owner to NHTSA Hotline for assistance.
TPMS Sensor False Alarms / Display Dropout
TPMS sensors give false pressure alarms and then register as dashes on dashboard. Sensors drop out sequentially (one tire at a time) and then reset after random periods, re-displaying actual pressure. Intermittent electrical communication issue with tire pressure sensors.
When: Occurs at random driving periods and speeds.
Symptoms owners cite: TPMS alarms sound for each tire sequentially; Tire pressure displays as dashes on dashboard; All four sensors drop out in sequence; Automatic reset after random period; Sensors resume showing accurate pressure after reset
Multiple Electrical Control Warnings / ESC / AWD / Lane Assist Malfunction
Multiple warning lights and system disables activate together: ESC message, all-wheel drive disable, lane assist, traction control light, parking brake light illuminating while driving. Electrical component cascade failure affecting multiple vehicle systems simultaneously.
When: First occurrence couple months after purchase (purchased May 2023); recurring intermittently.
Symptoms owners cite: ESC (Electronic Stability Control) warning message; All-wheel drive disabled; Lane assist malfunction; Traction control light illumination; Parking brake light on while driving; Sunroof acting erratically; Multiple warning lights simultaneously
Recalls/TSBs owners mention: Vehicle inspected by manufacturer; multiple dealer service visits attempted without lasting resolution. Vehicle under 1-year warranty when issues began.
Rearview Camera / Mirror Monitor Failure
Rearview mirror camera assembly fails, disabling rearview monitor and creating blind spot during reversing. Camera physically overheating to dangerous levels despite no visible damage.
When: Timing not specified.
Symptoms owners cite: Rearview mirror camera failure; Rearview mirror monitor disabled; Blind spot created while backing up; Camera assembly extremely hot to touch (burning hazard)
ABS Control Module Failure
ABS control module malfunction triggering warning lights and random or no-braking conditions. Dealership identified as 'known issue' but refused repair, stating vehicle unsafe to drive.
When: Timing not specified.
Symptoms owners cite: ABS warning light illumination; Multiple warning lights; Random braking or no braking response
Recalls/TSBs owners mention: Dealership service advisor denied repair citing 'known issue'. Other GM vehicles have recalls for same issue but 2020 Blazer not included. Vehicle returned to owner with safety concern unresolved.
Battery / Electrical System Power Loss
Vehicle loses electrical power and shuts down while driving. Battery cables found loose; battery tested as good despite recent replacement. Multiple power loss events with low battery notifications.
When: Battery replaced 2 years prior; failures occurring after that replacement.
Symptoms owners cite: AC panel lights inoperative; Vehicle stops and shuts down while driving; Low battery warning notification; Vehicle will not start after shutdown; Loose battery cable diagnosis made
Repairs/costs cited: Service department tested battery and reported it as fine despite low battery warnings and shutdown events.
Infotainment System / Startup Configuration Loss
Vehicle repeatedly asks if it is a demo vehicle at startup, losing user identification and vehicle key information between shut-downs despite owner signing in each time.
When: Recurring hundreds of times.
Symptoms owners cite: Demo vehicle prompt at startup; Loss of user profile information; Loss of vehicle key identification after shut-down; Persistent reoccurrence
Steering Assistance System Malfunction
Steering assist reduced warning message displays with reported loss of power steering function. Often triggered alongside coolant temperature sensor failures and ECT code issues.
When: Varies; often correlated with thermostat/coolant sensor failures.
Symptoms owners cite: Steering assist reduced warning message; Power steering loss reported; Message clears temporarily with battery disconnect; Message recurs at random intervals
Codes mentioned: P0128
Repairs/costs cited: Battery disconnect temporary workaround; typically related to thermostat housing assembly or cooling sensor replacement.
Synthesized from 32 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 2 most recent
When I parked and tried to turn off car it would continue to run. I had to put it in park and drive back to park several times before car would turn off. There’s a recall for this issue on other blazers and I feel 2020 blazers should be included. The dealer replaced the shifter assembly, cleared OTC
We have experienced 2 issues that are very well known issues, I will list them here. First, is the Shift to Park issue, that involves an electrical switch and wiring harness on the shifter assembly. Second, is regarding a "driver assist reduced drive with care" alert message that includes Diagnostic Trouble Code (DTC) P0128, but is actually related to either the engine cooling sensor or the…
Had electrical trouble with your 2020 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 2020 Chevrolet Blazer?
It's a documented issue but not catastrophic. 32 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 32 complaints filed, electrical issues most often appear around 51,250 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/2020/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.