[Teal95Jimmy]

That silver cylinder is called an accumalator and the wires that hook to it go to a pressure sensor. If the compressor turns on when you jump the wires there is either not enough pressure in the system or the pressure switch is shot. Another point to be taken is that you should never add freon to a leaking system (just quoting the back of the can) and if the system is low you should have it evacuated prior to filling the system to get all the contaminants out of the system (moisture and the reguar atmosphere)