The contact owns a 2020 Mercedes-Benz GLC300. The contact stated that while operating the vehicle, the 12-Volt battery warning light remained illuminated. The contact stated that while driving at various speeds, the vehicle shut off. The failure also occurred while driving on a busy freeway. The vehicle was towed to the local dealer who diagnosed that the STOP/START button was faulty and needed…
2020 Mercedes-Benz GLC-Class electrical problems
severe 10 complaints filed with NHTSA · avg repair $850 · see electrical across all vehicles →
Complaints
10
Recalls
0
Avg fix
$850
2fires
When does it fail?
Of the 10 electrical complaints filed for the 2020 Mercedes-Benz GLC-Class, here's the actual mileage breakdown — failures cluster heaviest at 0-25,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
The failure pattern owners describe
Buyer takeaway: Multiple owners report catastrophic electrical and coolant system failures causing fires, stalling, and loss of power at highway speeds. Mercedes has issued recalls without parts availability and blamed owners to drive carefully instead of fixing the underlying defect.
Ten complaints describe serious electrical and coolant system faults in 2020 GLC-Class vehicles. Two owners report engine compartment fires—one at 2,000 miles after dealership service, another shortly after purchase—both preceded by coolant-low warnings. Both vehicles totaled. Mercedes reportedly warned 800,000 owners of fire risk but lacked parts to fix it, advising owners to "drive particularly carefully." Mercedes later denied design defects.
Three owners report stalling or failure to restart: one at a traffic light using the START/STOP button after pickup from service, one at 30,000 miles (ignition failure, engine replacement recommended but never done), and one involving a 12-volt battery warning light that remained lit even after the dealer replaced the START/STOP button.
One owner experienced abrupt power loss and rapid deceleration on a two-lane highway at 65 mph with no warning lights—a frightening near-miss with trucks.
Rearview camera failure (no warning light) affected at least two owners, one related to NHTSA Campaign 21V354000. A center COMAND screen malfunction also disabled the rearview camera.
Multiple owners complained that recall parts for Campaign 21V354000 (electrical system) remained unavailable long after notification, with some offered over-the-air updates that also weren't ready. Manufacturers declined buybacks and offered minimal goodwill.
Same Mercedes-Benz GLC-Class electrical reports on nearby years: 2017 · 2018 · 2019 · 2023
Failure modes owners describe
Engine compartment fire / coolant system defect
Coolant level drops rapidly after dealership top-off, engine compartment overheats and ignites. Two owners report total loss. Both received coolant warnings and were instructed to shut down immediately. Owner reports indicate Mercedes issued warnings to 800,000 owners about fire risk but lacked parts to remedy the defect.
When: Within 2,000 miles of service; November 2021 and March 2022 for first owner; early in ownership for second owner
Symptoms owners cite: Coolant low warning alert displayed; Engine compartment smoke; Hood bulging; Flames visible in engine bay
Repairs/costs cited: Both vehicles totaled; no repair completed. Mercedes denied design defect and blamed hot surface ignition.
Recalls/TSBs owners mention: NHTSA Campaign 21V354000 (noted in other complaints); Mercedes issued warnings to 800,000 owners of fire risk but stated parts unavailable for immediate repair; owners advised to drive carefully
Power loss and unintended deceleration during highway driving
Vehicle abruptly loses power and decelerates on highway at highway speed despite accelerator pedal input. Engine revs but car slows rapidly. No warning lights or check engine lights precede or accompany the event.
When: September 2021; approximately 11 PM
Symptoms owners cite: Abrupt deceleration despite accelerator input; Engine revving but no power transfer; Rapid loss of speed; No warning lights or check engine light; Prior hesitation noted but not reported as diagnosed
Repairs/costs cited: Owner reported intent to take vehicle to dealer for diagnostic codes; no repair history provided
Vehicle stalls/fails to restart with START/STOP button malfunction
Vehicle stalls while driving or fails to restart after engine shutdown via START/STOP button. One case diagnosed as ignition failure requiring engine replacement; another involves START/STOP button failure.
When: At approximately 30,000-40,000 miles; after pickup from service; while stopped at traffic light
Symptoms owners cite: Vehicle stalls while driving; Fails to restart via START/STOP button; 12-Volt battery warning light remains illuminated; Stalling occurs while driving at various speeds including busy freeway
Repairs/costs cited: One vehicle: STOP/START button replaced but failure persisted. Second vehicle: Engine replacement recommended but not completed; vehicle remained at dealer.
Recalls/TSBs owners mention: Manufacturer declined to buy back vehicle and offered two-year service plan with free annual oil change
Rearview camera failure with no warning
Rearview camera ceases to function during reversing with no illuminated warning light. Related to NHTSA Campaign 21V354000 (Back Over Prevention, Electrical System).
When: At approximately 30,000 miles
Symptoms owners cite: Rearview camera inoperative during reversing; No warning light illuminated
Repairs/costs cited: Vehicle not repaired; recall parts unavailable at time of complaint
Recalls/TSBs owners mention: NHTSA Campaign 21V354000 issued; recall parts not available; manufacturer provided no assistance
Center COMAND screen malfunction disabling rearview camera
Infotainment screen fails to display, eliminating rearview camera feed when vehicle is in reverse. Dealer attempted repair but issue persists.
Symptoms owners cite: Center COMAND screen displays incorrectly; No rear camera view available when reversing
Repairs/costs cited: Dealer attempted repair; issue remains. Replacement parts ordered.
Recall parts unavailable (21V354000 electrical system)
Owners notified of NHTSA Campaign 21V354000 (Back Over Prevention, Electrical System) but repair parts unavailable. Manufacturer exceeded reasonable timeframe for recall completion. Some offered over-the-air (OTA) update as alternative, but updates also not yet available.
Symptoms owners cite: Recall notification received; Parts or OTA updates unavailable
Repairs/costs cited: Recall repairs not performed; owners placed on waiting lists
Recalls/TSBs owners mention: NHTSA Campaign Number 21V354000; manufacturer stated OTA update not available and placed owners on waiting list for notification when available; parts distribution delayed beyond reasonable timeframe
Synthesized from 10 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 3 most recent
When using engine start/stop function, over the course of 3 days after picking up the car, when at a light, the car did not start back up.
The contact owns a 2020 Mercedes-Benz GLC300. The contact received notification of NHTSA Campaign Number: 21V354000 (Back Over Prevention, Electrical System) however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced…
Had electrical trouble with your 2020 Mercedes-Benz GLC-Class?
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 Mercedes-Benz GLC-Class?
It's a meaningful issue. 10 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $850.
At what mileage does the electrical typically fail?
Based on the 10 complaints filed, electrical issues most often appear around 27,225 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/Mercedes-Benz/GLC-Class.
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.