I can't say if one wire should be grounded (to the pump body) or not. I've not had it apart yet! However, assuming that one end should connect to the pump body (it seems reasonable), then the other end also connects to the pump body through the coil in the pump motor. Between one wire and body you should read 0 Ohm (or near 0), between the other wire and the body you should read the resistance of the pump motor. On the 900 this is only 0.2 to 3.0 Ohm. So you'll need a good meter to measure the difference.
Don't know if this helps!
Don't know if this helps!