I have central Heat and air and my air works just fine but when I turn the heat on it works just fine also but it will not shut off unless I shut the switch off at the thermostat and it is digital is that my thermostat?

Crossed wire.
Thermostat wiring has shorted.
Thermostat defective.


If replacing by a good quality Honeywell or White Rodgers.

Could be a sticking heat relay at the furnace?