crankshaft sensor

The Crank Sensor will have no effect on the battery draining. Check your blower motor, they have an unusual amount of electronics and they over heat and short out. Then they drain the battery, pretty common problem. Just unplug it when you park your car and and see if the battery stays charged. There are 2 Crank Sensors and each costs about $95 dollars. To do both takes 1.8 hours and I would do both.