Q: How to troubleshoot electric rearview mirrors on Buick Rainier and Chevrolet Trailblazer?
A: The electric rearview mirrors have two motors for adjusting the glass up/down and left/right. To troubleshoot issues, begin by operating the mirror control switch through all functions while listening for motor sounds. If the motors can be heard but the mirror doesn't move, it indicates a problem with the drive mechanism inside the mirror, requiring replacement. If there is no sound and the mirrors don't operate, check the Fuses and ground connections. If it still doesn't work, test the wires for voltage and check the circuit for opens/shorts. If there is voltage, test the mirror and replace it if it fails.