GMC Terrain: Keys, Doors, and Windows / Doors

Safety Locks

The rear door safety locks prevent passengers from opening the rear doors from inside the vehicle. Manual Safety Locks If equipped, the safety lock is on the inside edge of the rear doors...

Liftgate

Warning Exhaust gases can enter the vehicle if it is driven with the liftgate or trunk/hatch open, or with any objects that pass through the seal between the body and the trunk/hatch or liftgate...

Other information:

GMC Terrain 2018-2023 Owners Manual: If the Off Indicator Is Lit for an Adult-Sized Occupant

If a person of adult size is sitting in the front outboard passenger seat, but the OFF indicator is lit, it could be because that person is not sitting properly in the seat or that the child restraint locking feature is engaged. Use the following steps to allow the system to detect that person and enable the front outboard passenger frontal airbag: Turn the vehicle off...

GMC Terrain 2018-2023 Owners Manual: Seat Belt Extender

If the vehicle's seat belt will fasten around you, you should use it. But if a seat belt is not long enough, your dealer will order you an extender. When you go in to order it, take the heaviest coat you will wear, so the extender will be long enough for you...