Today while I was on the computer I started to feel like the heat was on. So I went to the thermostat and it said it was 86 inside the house and the heater was on. I don't know how this happened, I had the a/c on at 79 and it just suddenly stopped and switched to heat. I quickly turned the heat off and switched it to a/c. I noticed that barely any air was blowing out of the vents and it was not cold air. Then I went outside and noticed the fan wasn't running or making any noise. I checked the contactor and it looked fine. I did notice where a bunch of wires are connected to this little black box next to the contactor had 2 burnt connections. I don't know what this is called, but does anyone know if this could be the problem? I'm don't know anything about a/c units. I wuld like to get this fixed asap but not spend a grip of cash for it. If I can fix this myself please let me know. I'm sure I can remove that black part and replace it if needed. I'm just not sure what it is called.

Ok I found out what that black piece is called. It's the contactor, there are two burnt contacts on it. Where can I buy a replacement?

Ebay or a local HVAC company.