I have experienced the same situation with my blower. It sounds like it is working very hard but I do not get a strong force of air coming out of the vents. I was begining to wonder if this was how it was designed in the 92-93 era since I have seen others post similar problem. In most other cars if you turn the fan to high you get air blowing strongly out of the vents but not in my 92 500SEL, any ideas? What should the system be set to in order to get forceful air coming out of the dash vents?