See also:

How the System Works
URPA comes on automatically when the shift lever is moved into R (Reverse). The rear display briefly illuminates to indicate the system is working. URPA operates only at speeds less than 8 km/h ...

Reporting Safety Defects to General Motors
In addition to notifying NHTSA (or Transport Canada) in a situation like this, please notify General Motors. Call 1-800-521-7300, or write: Buick Customer Assistance Center P.O. Box 33136 ...

Compass Variance
Compass variance is the difference between earth’s magnetic north and true geographic north. The mirror is set to zone eight upon leaving the factory. It will be necessary to adjust the compass ...