It's a momentary contact switch for starting the motor. If you bypass it, the dryer will start as soon as the timer is turned on. Terminal 4 to 2 are the momentary contacts. Terminal 4 to 3 is connected internally. You can certainly jump 4 to 2 to start the motor if you want but I wouldn't leave it that way. This dryer has a belt switch. If the belt breaks and you have the start switch bypassed, the motors going to keep running and the heat will stay on as well.