It's a variable demand set-up, no clutch and the compressor displacement is controlled by the climate control unit. Don't know if control signal is a pulsed duty cycle deal or a variable current/voltage (or both).

You can monitor the duty cycle percentage request from the ECU using SDS and under actuations you can manually manipulate the compressor settings.

Stupid question but you did remember to plug the electrical connector back into the remanned compressor? You mentioned it wasn't an MB replacement part, where did you get it?

SDS seems to also indicate that 750ma should be the maximum current draw possible, is it possible the compressor you got doesn't know about variable demands?

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