When to replace the whole mirror unit (and when just the glass will do)

A 5-point checklist with photos of typical impact damage, plus when an internal motor failure means glass-only won't cut it.

You hit a hedge. The glass is cracked. Cheap fix or full unit? Here's how to decide in under 30 seconds.

Glass-only fix is enough if...

• The backing plate behind the glass is intact and flush in the housing
• The housing itself has no cracks beyond cosmetic scuffing
• The mirror still moves freely up/down/left/right under electric control
• The indicator (if applicable) still flashes

Full unit replacement is needed if...

1. The housing is cracked through to the inside
2. The backing plate is cracked, missing or misaligned
3. Electric adjustment is dead in one or both axes (motor failure)
4. The mirror is loose at the door hinge (mount damage)
5. The indicator lens is broken (only on integrated-indicator models)

The motor-failure gotcha

Replacing the glass on a unit with a dead motor "works" until you adjust the seat and want the mirror to follow. Don't bother — replace the whole unit.