For *most 123 chassis cars made from 1977 to 1985 and *mostl 116 chassis sedans built from 1973 to 1980. This repair guide will take you through the process of how to properly remove your heater blower motor and replace the motors two brushes. This is the most common reason for failure. 240D 300D
If your blower motor has been intermittent or some days it wont come on until you drive for a while your motor brushes are most likely at the end of their life. This is something you may just want to replace as a preventative measure. 20 year old heater motor brushes are very prone failing at any time. If it has not failed yet it most likely will sometime soon.
Along with this detailed instruction guide I will provide you with a set of new brushes (which I have diligently sourced). You will need a soldering iron and a few common hand tools to complete the job. If your car has a over 150,000 miles on it or you know the heater motor has been run a lot, the best time to do this job is now! Do not wait for it to quit on you on a cold winter morning.
IMPORTANT: If you are planning to replace your heater motor brushes I highly recommend you have a high output soldering pencil on hand. If you don't, then I recommend you purchase the one we sell on our website. It is a powerful 60 watt unit and works great! Look below to see our soldering pencil.
***WARNING WARNING: There are a few late 123 chassis out there that have Siemens 1BB52 13V 6707/1 34" blower motor. These brushes will not work in your motor.Check your motor before ordering. If you order in error these are not returnable. The brushes will fit all Bosch motors ONLY ONLY ONLY!!!!.
Here are a couple pictures of the Siemens motor brushes. Note the difference in the style of motor and the width / cut of the brushes. The fan has to come off to get to the brushes on the Siemens motor