A/C Problem
 

Ok, so my mom's 2000 S10 ext cab 2wd pickup is having issues. There are no blown fuses, but the A/C compressor is not getting 12v, and won't kick on. The heater seemed to stop working at the same time, and I discovered she had let the coolant get WAY low (small leak i think). So, refilled coolant, and the heater seems to be working great, although it's 90 fricken degrees, but thinking there might be an air bubble in the system, or..........? Please help.

I am searching, somewhat frantically, but having no luck

if the refridgerant level is low the ecm won't ground the relay to energize the compressor clutch