A malfunctioning HVAC blower motor regulator can cause the blower motor to operate below the requested speed or not at all. Updated regulators are available; the blower motor and cover need to be replaced at the same time to upgrade the system.
Car Problem Reports
Mercedes-Benz E300 Malfunctioning Regulators May Cause Blower Motor Failure
Mercedes-Benz E300 Problem
Average Mileage: 173,500 mi (167,000 mi - 180,000 mi)