Nice shiny new 4 terminal solenoid arrived today.
I doesn't work....
Negative to mounting plate, Positive to ignition terminal, no healthy clunk, no continuity between the threaded terminals.
Trouble is I didn't test it until after I had fitted it to the car and found that the starter motor didn't work. All outdoors in the cold, near gales that we've got at the moment.
3 terminal solenoid & temporary switch now back in place and all working again.
Am I missing something else before I put the new solenoid back in the post?