MDX V6-3471cc 3.5L (2002)
actuator.
20. Check for voltage between the B20 and B19 terminals while moving the driver's mirror from up to down.
Does the voltage change from about 1 V to 3 V?
YES - Substitute a known good passenger's multiplex control unit, and recheck. If the systems now work OK, replace the original passenger's unit.
NO - Repair open or short in the GRY wire. If the wire is OK, the left power mirror position sensor is faulty; replace the left power mirror
actuator.
