The blower motor just stopped working.

Hot day, long trip, aircon on; started smell like something electrical burning. After an hour, the fan stopped. I removed the fan; simple to do; takes about 10 minutes. Observed the motor commutator was damaged. Bought a new motor (not including whole assembly with the fan cage) online for about $140. The whole assembly at Mercedes dealer is over $1200; online prices are several hundred. The problem is that the fan cage is a plastic part and needs to very carefully removed off the motor shaft; try spraying with liquid wrench, support the fan with some wooden boards and tap down on the motor shaft until it releases. Upon reassembly, the fan cage must be in balance with the motor or else you'll get vibrations at different motor speeds (as unfortunately I did). It took me about 2 hours to reassemble, test for vibration, take blower out of its airbox, visually observe out of balance of the fan cage, heat to soften the fan cage near its spindle and bend it in order to make it straight and balance. I finally achieved balance to perfection with no out-of-balance vibration noise, got it re-installed. It works like new for $140. It would only be about a 30 minute job if you buy the whole blower assembly with the fan cage; see www.autohausaz.com

The sensor in the front of the car is for outside air temperature it shouldn't stop the blower motor from working.I am not very knowledgeable in Mercedes but if you need test procedures wiring diagrams ect...... There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online