Heat pump won't work in heat mode... blows fuse in thermostat every time . A/C works fine. Disconnected white wire for heat at outside unit and did not blow fuse... wire shorted?? Please help

It certainly sounds like a shorted white wire. It's easy to find out by simply swapping the white for another color if there are any unused wires.
The problem could also be a short outdoors in a wire only powered in the heating mode. One that comes to mind is maybe going to the reversing valve if the valve is 24v.