Some observations about W123 blower motors -
First check the 16 amp fuse to make sure it isn't melted (cheap aftermarket plastic fuse) or melting the fusebox itself. Some W123 fuseboxes have a pair of unused fuse contacts. In extreme cases it may be neccessary to transfer the blower wire-terminals to those unused contacts. Or else wire in a heavy-duty inline fuse holder.

There are differen design W123 blower motors. On some, like an '80 300D I repaired many years ago, the brushes were accessible. Others, like the one in my '82 240D, are not.

Many of the plastic W123 fans I've seen, have a steel hup pressed onto the motor shaft. It may be impossible to remove the fan-blade without destroying it.

I was recently told that Mercedes now wants around $800 for a new W123 blower moter, including the fan-blade and plastic bottom cover!

But, I just got a good used one from the Virginia-Beach Pick-N-Pull for $15!

Good luck & Happy Motoring, Mark

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DrDKW