'93 500 SEL... HVAC blower motor doesn't seem to generate sufficient air volume... voltage at blower motor is approx. 6.3 volts when speed thumbwheel is set at "MAX". Is this voltage too low? The W140 AC Electrical Test Program doesn't list a maximum voltage, only that nominal value for "MAX" is > 5 V, blower motor running.

Blower motor speed is adjustable from "MIN" to "AUTO" but no further speed is noted when set to "MAX" or Defrost is engaged.

The vehicle still has the old style blower regulator; cabin air filter is new.