Came out to call to perform preventative maintenance on 2 systems. Customer stated the upstairs unit wasn’t cooling at all and the outside ac wasn’t on either, but the blower was blowing air. I checked system over and found the unit locked out from high pressure switch. I reset set the system and couldn’t repeat the fault. System wasn't completely filthy, but I cleaned it thoroughly and the other condenser as well. Replaced customer supplied filters. Checked capacitor, contactor, compressor, fan motor, amps, temperatures and pressures of both units. Upstairs system is cooling properly now and downstairs unit was as well. Made customer aware of potential intermittent faults on upstairs unit and to keep an eye on the system, and give us a call if it acts up again.