MTFCA Forum

I have a Question: I am working on restoring my switch plate for my 1924 Touring, the back side terminal cover is this one on the left, it uses tabs that are folded back onto the piece to hold it together. It also has 6 terminations.

Because I still do not have this project done, I have decided to use different switch assembly that I have, temporarily. It uses pin,s not tabs to hold it together, and has seven terminations.

This switch is from a 1926 Chassis I purchased several years ago, and then repainted it. It is in very good shape and my plans are to use it on my speedster project. That is why I am "borrowing" it for now.

The nuts and bolts of my question is: because of this extra termination, will there be a problem wiring it up, will I, in order to make it work need to add a ground to it as I believe the "extra" lug is for a ground, where-as the earlier one does not have one.

It will be several weeks before I will finish up the original one and want to in the mean time drive my T.

The arrows at top show the different mounting points, the big arrow on the right is pointing at the termination in question.
Sorry the picture is not better, taken with my phone. JH

Hope this helps.

By Dan Treace, North FL on Sunday, June 26, 2016 - https://www.mtfca.com/discus/messages/5 ... 1466967175
The April 1 1920 Service Bulletin notes the 'Grd' terminal is used when testing the switch, with all harness removed from the switch. 110v test lamp is put to the ground to see if there is a ground issue with the three positions of the ignition ( Bat, Off, Mag ) of the switch.
Not every mfg. did that Grd terminal on the switch so some don't even have it.

Normally never used to ground the switch to the chassis, as the metal dash panel the switch is mounted to does that if needed, but grounding the switch plate isn't nescessary. So leave it empty
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There was another reason for that Ground terminal that is not often mentioned.

Magnetos need a ground to stop the sparks from happening.

Cars with accessory Magnetos needed a functional ground in the off position to shut off the engine.