AC compressor does not work

For the A/C issue, we at RepairPal put together an inspection sheet to help folks with these types of problems. https://repairpal.com/estimator/air-conditioning-diagnosis-cost The gauge issues are a separate inspection, best to have the Instrument Panel scanned. here are some shops: https://repairpal.com/mercedes-benz-repair-in-spring-texas

to answer your question about your ac,you have to erase the trouble codes in the hvac module.it'll set a low pressure code and will not activate the ac compressor even though you change it. and about your cluster get it check out.