GMC 2004 Canyon - Manual (Page 119)

Temperature Display Operation
The outside air temperature is displayed in the window
located at the lower center of the mirror face.
Press and hold the far right button for four seconds and
release. This will change the temperature reading
between degrees Fahrenheit, degrees Celsius, or turn
the display off.
Cleaning the Mirror
When cleaning the mirror, use a paper towel or similar
material dampened with glass cleaner. Do not spray
glass cleaner directly on the mirror as that may cause
the liquid cleaner to enter the mirror housing.
Outside Manual Mirrors
Adjust these mirrors by hand so that you can just see
the side of your vehicle when you are sitting in a
comfortable driving position.
The mirrors can be folded inward to prevent damage
when going through an automatic car wash. To fold,
push the mirror toward the vehicle. To return the mirror
to its original position, push outward. Be sure to
return both mirrors to the unfolded position before
driving.
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