Theory sounds OK, but actually, you'll need to add a manual heater valve in place of the bypassed servo or you'll have heat all the time. Also, the temperature wheel potentiometer probably won't be up to the load of the blower motor. You'll need another setup for that.
If someone could design a kit to fully bypass the servo, they'd have the gratitude of many afflicted Mercedes owners.

Happy Motoring, Mark

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DrDKW