Thanks Chris, that makes sense OK, but I was expecting one of the wires going to the w/w motor to be zero and the grounding from the stalk to travel along it to complete the circuit - with all three wires positive there;'s no way for the ground to get there ?
I'm now thinking that the motor has broken and is shorting out the wires - I did the test with the plug connected because I could see no way to remove it - any clues ?