wires on the starter motor

[panalvan]

Just been over to a friend as there van wont start got under it and found a wire had come off the solinoid it was a spade terminal.My question is my 1970 van has one spade terminal wire on the solinoid but this 1972 van has two which go to the solinoid on a common spade.What does this extra wire do as i plugged it back on .Made no diffrence until i tapped the solinoid with a hammer(new solinoid needed)now starts
Cheers

 

[Trikky2]

The 72 van would originally have had a diagnosis socket and the extra wire you mention goes to that. It allowed the computer to turn the engine over during battery and compression testing.

(Computer diagnosis is no longer used - nobody has the equipment anymore - so can be discarded).