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What 179 owners told NHTSA about the 2020 GMC Terrain

These are the actual owner complaints behind this car’s reliability verdict, filed with the federal government, unedited. They’re unverified reports, not confirmed defects: read them as leads for your pre-purchase inspection, not a diagnosis.

All (179)Crash / fire / injury (10)Brakes (64)Engine (54)Electrical system (26)Fuel system (26)Transmission & drivetrain (25)Speed control (11)Driver assistance (8)Backup camera & sensors (6)Body & structure (5)Visibility & wipers (4)

1 of 179 complaints match · Body & structure · crash/fire/injury only · clear filters

Dec 19, 2024Visibility & wipersBody & structure1 injury

The contact owns a 2020 GMC Terrain. The contact stated that rain water had leaked from the sunroof drainage into the vehicle causing the floor carpets to become saturated with water and mold had developed inside the vehicle. The contact also discovered a pool of water inside the spare tire well. The vehicle was taken to the local dealer who replaced the sunroof motor and sunroof liner, unclogged the sunroof drainage assembly and replaced the carpets. The contact indicated that later the failure had reoccurred although the sunroof drainage assembly was consistently unclogged each time the vehicle was in for service. The contact had also experienced respiratory illness due to the mold present inside the vehicle. The manufacturer was notified of the failure but no assistance was offered. The failure mileage was 12,300.

NHTSA ODI 11631628

Working with the data? Download all 179 complaints as CSV · fetched from NHTSA July 10, 2026

How to use these: a complaint is one owner’s report, filed voluntarily and published unverified. Patterns matter more than any single story. If several owners describe the same failure at similar mileage, put that system at the top of your pre-purchase inspection list. Back to the full 2020 GMC Terrain verdict →