To replace the heater blower switch on a 1975 Mercedes 450SL convertible, first disconnect the car battery to ensure safety. Remove the dashboard cover and the panel surrounding the switch to access it. Unscrew the old switch from its mounting and disconnect the wiring harness. Install the new switch by connecting the wiring and securing it in place, then reassemble the dashboard components.
Take it into the shop. It's a whole lot easier.
385 euros @ mercedes main dealer.
http://202tech.mkosonen.com/howto/blower.html detailed and illustrated how to with no need to visit MB stealership
have you checked the fuse if so then you will need to replace the resistor for the blower hig and low dettings have you checked the fuse do you have 12 volts to blower if so then you will need to replace the resistor for the blower replace the blower motor
how do you change heater blower resister merc a class
Continental/VDO New A/C Heater Blower Motor PM4820
Remove the wiring harness to the heater blower fan. Remove the retaining bolts. Remove the fan from the blower. Reverse the process to install the new heater blower fan.
Replacing the heater blower in a Mercedes 300SL can be somewhat challenging, primarily due to the car's age and the complexity of its design. Accessing the blower motor typically requires removing several components, which can be time-consuming and may necessitate specialized tools. If you're not experienced with automotive repairs, it may be advisable to consult a professional mechanic to ensure the job is done correctly.
it is right under the glove compartment
replace heater relay and or heater blower motor
Blower is a dual squirrel cage unit located under the wiper arm assembly. You will need to remove this and the engine bay fire wall center section to gain access.
Check fuse box - fuse #14