Can anybody tell me why you'd need a tenth post on the coil box? I know one goes to the terminal block, then there are the four for the timer and the four for the spark plugs. Where does this tenth post lead? I've seen boxes with ten of them installed, and there are holes in the firewall for ten posts to come through, but all the wiring diagrams I've looked at only show nine of them. Any idea what this spare post would be for?

On cars with an ignition switch on the dash, the power from the battery (if there is one)and the magneto are both routed to the switch which selects one or the other. The output of the switch runs to the ninth contact on the coil box. On cars with the ignition switch on the coil box, both power leads must enter the coil box and the selection is made on the front of the box, thus ten contacts.

Jared Vuckart:

One hole for the battery and one hole for the Mag.

1909-1918 (switch on box), ten. 1919-1927 (switch on dash), nine.

Thanks guys. Another T mystery solved.

1919 Hack - switch on box - box on firewall

The first two pictures were taken just after we got the T home and the last when we pulled it out of the barn.

I found a couple pictures of the other side of the firewall - these were also taken shortly after we got the T home