Mirror Won't Fold In or Out

Your GM truck or SUV's side mirror doesn't retract when you press the button — either it's completely silent, or it makes a sound but doesn't move.

What's actually broken

The electronic retraction feature runs through a small plastic spur gear buried inside the mirror's motor housing. That gear is threaded onto a metal worm gear driven by the electric motor. Over time the plastic becomes brittle and either cracks or strips its teeth — and once that happens, the motor can spin freely without ever moving the mirror. This is the cause about 95% of the time.

How to tell if it's the gear

• You hear a faint electric buzz or vibration when you press the fold button, but the mirror doesn't move — this is the classic sign of a stripped gear spinning freely.
• Total silence, no sound at all, usually points to the motor itself (see motor grinding/failure) rather than the gear.
• If the mirror glass vibrates or feels loose at highway speed, that's a secondary symptom of the same broken gear — without the gear holding tension against the worm drive, there's play in the mechanism.

The fix

Replace the plastic gear with our redesigned, strengthened version — metal where the original GM part used plastic. Our mail-in gear + motor repair service is $279 for one mirror ($549/pair), or $45 ($85/pair) if you'd rather install the gear yourself. See full pricing.

Curious how we figured this out in the first place? Read the full story.