The fluid sensor has a slight time delay hinged float switch. It will slip into the tanks rubber gromet in any position,but only one position is correct. Take's two people to verify this test unless you have a ohms meter. One in the car with the switch on watching the gauge. The other has the sensor pulled out of the tank,but still has the wiring connected. It's been years and trying to remember where the sensor should be pushed back into the tanks rubber groument,so that the float would hang down or would swing upward. Try it both ways while holding it and keeping in mind the hinged float will be trying to float upward with a full tank. Squirrel Crusher