Connect pin #4 to ign ( master switch ) 7-30 volts positive.
Connect pin #2 to one of the sender leads. ( does not matter which sender lead )
Connect the other sender lead to a good engine ground.
Connect pin #5 to the same engine ground as the sender.
Note! Connecting pin #5 to the same ground point as the sender ground will help reduce the pointer fluctuation when a heavy load is applied to the electrical system. ie. lights, alternators, electric pumps etc.