The large line(suction line) is supposed to be hot when in the heat mode.
You may not have let it run long enough in defrost to cool down.
Unless you turned off power to the air handler when you made the jumper connection you will hear noise at the board.
If the valve is sticking you can set the unit to run in COOL,lower the thermostat as low as it will go(usually 50 degrees).
At the defrost board remove one wire going to the RV.
Continuosly touch and remove the RV wire to its' terminal until you hear the swoosh sound on the valve changing over.
If you hear the swoosh sound as soon as you remove the wire,it is not stuck.
Since it is cold at the unit,use your meter to check continuity through the defrost thermostat to verify it is good.(remove the wires from their terminals first)