I don't know anything about 201's, but I've gotten to the blower motors on my other MB's are on the interior side of the firewall, and I'd be surprised if yours is different. Mine are passenger side, accessible by removing panelling underneath glovebox on passenger side. From outside the car you should be able to see how the air gets to it. It should also be downwind from the cabin filters. Are your cabin filters in the engine compartment somewhere?

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