Help 2001 Dakota

Hi everyone, I have a 2001 Dakota R/T. I have owned it since new! I love this truck and still drive it everyday. I have 2 problems I need help with. I have an A/C problem. I have no A/C.I have replaced the canister/and little filter in the line/a/c pump itself/ we jumped the pump directly to battery and charged the system correctly so it has correct pressure so it is not a high low problem. I replaced the relay and jumped from pin 30-87 and had power. I followed everything to the tee. Here is the issue, no power to the high/low switch on the canister. I have already switched the blower motor and resiter and that works perfect. Just no a/c. And yes all fuses have been removed and are good. Any ideas.

Problem#2 The + battery terminal corrodes really fast. I clean it and 2 weeks later it is green and nasty. Please help.