Remove the plastic covers around the wiper, between base of windshield and false firewall.
Disconnect feed wires between wiper motor and harness, remove the mounting screws, should be several around wiper head.
Remove the wiper assembly, blade may remain.
You've now exposed the blower housing.
Remove the heater covers, should 2-3 clips on all four sides.
Remove the blower motor clamp, disconnect feed wires to regulator under the blower and remove blower and cages.

Installation is the reverse.

It's all in the factory manual.

Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles