Trying to see if there are any HVAC pro's here. Couple of hours ago it started getting "stuffy" in house. Got up and checked thermostat and by God it was approaching 80! Had it set to 74. Well I changed the thermostat to one of the older ones we kept, no change. Checked all the breakers-fine. Climbed in attic, removed cover to view cage fan. There is a microswitch on left side of cover so when removed-disconnects circuit. When depressed I just hear a low buzzing noise. I'm hoping this is just the capacitor. All was running perfect 2.5 hours ago! Any advice appreciated.