Couple of days ago my ac stopped blowing cold air. vents had warm air coming out of it. I went to check the condenser unit outside and found that the fan and the compressor were not turning on. When the thermostat sends the signal, I can hear the contactor click but no buzzing noise. I thought it might be the Capacitor so I replaced it but it didn't fix the problem. I'm now thinking its the contactor. I noticed the middle of the contactor looks burnt out? How can I tell for sure? Can I test it somehow after turning off the power?