No other issues were noted the rest of the way to work or on the drive home this evening. I checked the gas cap when I got to work, no help

My fan motor is not running for heat and air. The motor is fine and some say resistor some say switch and this place say control panel? It was running then would hesitate and slow down then speed up and when I started my truck today nothing? Could it be the resistor? I hope so that's only 100.00. How can I tell? Some say the fan would run on hi only if it is the resistor and some say that isn't true....please help

I called the dealership and they want 85.00 to check out the whole system to see if that's the problem. If blower motor is bad, the part itself is 500.00 plus labor and something else that has to be put on as well. I know they charge out the butt and I am hours from the nearest dealer. Where is the blower motor located so I can check it out for myself if the relay is not the problem? Also, what else would cause the blower motor to just up and quit without any signs?