B46 w/ same problem
I am in the middle of the float switch issue in the aft head on my '07 46. Picked up a new float switch last week. It comes with stranded, untinned, bare wires. I crimped on spade connectors (w/ heat shrink tubing) & tested it before putting it in the sump. I checked continuity & the switch works just fine - up circuit closed, down circuit open.
I plugged the new switch onto the terminals & the pump energizes whether the switch is open or closed. I had to unplug the switch & manually use the on/off switch to stop the pump. Called the dealer who said that the relay attached to the manual switch is bad. And now it's another $45.00 for the relay and I will see what happens this weekend.
BTW - I checked the original switch and found a bad crimp at the spade connector. (I probably broke it when disconnecting.) So I crimped on a new spade connector & I now have 2 good switches. I intend to use the new switch because the rubber grommet on the original is somewhat distorted and may not form a watertight seal.
Regards.
DH