300TE, that's a W124 chassis.

First, the fuse is a flat fuse (30 amps ?) that is located in a holder off of the top of the LF strut tower. Check this first.

Second, if the blower does not work on any setting of the pushbutton unit, check the plug for the blower motor/regulator. It is a 3 pin plug located just behind and above the brake booster. I believe the wires are brown (ground), black (power) and yellow (control voltage). Should be battery voltage between the black and brown (ignition on). Then from the yellow wire should be in the range of 4 to 5 volts.
If these voltages are ok, then the blower motor AND/OR the blower regulator are bad. If cannot know which is bad until you take it all apart. They are located 6-8 inches below the wiper motor.

Tech Tip of the Day!
When removing the wiper motor, beware of prior windshield installers that have used way too much goop to glue the window in. Windshields crack if you sneeze or lean on the edge to hard. Be carefull!

When in doubt, let an experienced MB Tech do the job.

------------------