looch
Veteran Member
I recently acquired a 1951 Massey Harris Pony. It was running, but the wiring was scary - cracked insulation, fraying at the terminals, etc. I bought a new harness which came with a basic "connect A to B" instruction list. I compared it to the shop manual's wiring diagram, and they match. Here's the shop diagram:
A previous owner had replaced the generator/light switch with a 3-position light switch. This meant having to do something with generator's F terminal (blue wire). Simple solution (though not ideal) - routed to a grounded switch. So this switch is performing lighting duty only.
My confusion lies around the starter button. I can't make sense of the diagram - it has the starter and ammeter/battery connected to the same terminal on the factory 3-position switch. Press the starter button, all you do is create a loop through the negative side of the circuit i.e. nothing happens. In order for the starter button to engage the starter solenoid, it needs to complete a circuit through ground. To me, then, that means that the factory 3-position switch must have continuity from ground to the terminal onto which the starter is connected. But if that were true, the battery would be in a constant short circuit as the ammeter/battery shows as being connected to that same terminal.
Is the shop diagram messed up? Am I? For reference (and for my own sanity) I photocopied, whited out, and re-drew the wiring diagram to correspond to the "as-bought" condition:
A previous owner had replaced the generator/light switch with a 3-position light switch. This meant having to do something with generator's F terminal (blue wire). Simple solution (though not ideal) - routed to a grounded switch. So this switch is performing lighting duty only.
My confusion lies around the starter button. I can't make sense of the diagram - it has the starter and ammeter/battery connected to the same terminal on the factory 3-position switch. Press the starter button, all you do is create a loop through the negative side of the circuit i.e. nothing happens. In order for the starter button to engage the starter solenoid, it needs to complete a circuit through ground. To me, then, that means that the factory 3-position switch must have continuity from ground to the terminal onto which the starter is connected. But if that were true, the battery would be in a constant short circuit as the ammeter/battery shows as being connected to that same terminal.
Is the shop diagram messed up? Am I? For reference (and for my own sanity) I photocopied, whited out, and re-drew the wiring diagram to correspond to the "as-bought" condition:
