The fan, heat , and a/c does not work. The heater core has been diconnected.

I do not understand your question. Need more data. If the blower does not run, check the fuse, then the physical appearance of the blower resistor connector block. Using a test lamp, verify power at red wire of resistor connector. I the resistor is deformed, you can buy a blower resitor, and connector pigtail as a replacement. Basically, if you have power and ground to the blower it will run unless it has completely failed. Since you state that all of the components are inoperative, I would begin with checking power distribution by first checking power to blower motor.