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ML500 2006, Air compressor for suspension reconditioned. The engine runs when the compressor is not connected, but when you connect the compressor the engine does not crank What could be the problem?
I am unfamiliar with that system, but I can offer a logical hypothesis.
There may be a pressure sensor built into the compressor module that is pulling down the 5v reference circuit, or it could be that the compressor is on the data network, pulling that down.
Maybe someone with some more experience has a better idea.