Here is what the model 3 manual says about folding mirrors:
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Learn how to adjust and control both interior and exterior mirrors.
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Folding Mirrors
To manually fold and unfold exterior mirrors (for example, parking in a narrow garage, tight space, etc.), touch Controls > Fold/Unfold Mirrors.
When you manually fold the mirrors, they remain folded until your driving speed reaches 31 mph (50 km/h) (or until you manually unfold them by touching Controls > Unfold Mirrors).
Note
You cannot fold a mirror when driving over 31 mph (50 km/h).
To set the mirrors to fold automatically whenever you exit and lock Model 3 touch Controls > Mirrors > Mirror Auto Fold. The mirrors unfold automatically when you unlock Model 3.
You can also set mirrors to fold automatically whenever you arrive at a specific location, which saves you from having to manually fold them each time you arrive at a frequented place. To set this up, stop at the location you want to save (or drive at less than 3 mph (5 km/h)), and fold the mirrors. Save Location appears briefly below the Fold Mirrors control. Touch again if you no longer want mirrors to automatically fold at the location.
Note
When you leave the saved location, mirrors remain folded until your driving speed reaches 31 mph (50 km/h), or until you touch Controls > Unfold Mirrors.
CAUTION
Mirrors may not automatically fold if you return to a saved location and are driving faster than 3 mph/5 km/h.
Note
You can override the automatic folding/unfolding of mirrors at any time (for example, Model 3 has no power) by pushing the mirror assembly away from you to unfold, or pulling it toward you to fold.
Note
If you expect ice to accumulate when Model 3 is parked, turn off Mirror Auto Fold. Accumulation of ice can prevent exterior side mirrors from folding or unfolding. See
Cold Weather Best Practices for information on how to ensure your mirrors function properly in cold weather.
You can integrate auto-folding mirrors with HomeLink (see
Smart Garage). To enable, go to HomeLink > Auto-Fold Mirrors when Nearby.