I need to replace the A/C compressor,filter drier, and the expansion valve. have no idea as how to access the expansion valve which I assume is under the dash somplace, The rest of the job is pretty cut and dried, but I can not find a diagram of the cooling coil.Thank you.
I’ve never done one on a Mercedes like this but the expansion valve is usually located on the evaporator. This generally means removal of the evaporator case which may or may not entail removal of the dashboard.
Some evaporator jobs can be a real pain in the neck.
If no one responds to this question about evaporator removal details you may have to find a service manual that lays this out or do some internet fishing.