Ignition Switch I.D. ??

I found this switch (pics below) in my stash of parts I've had for eons, but I don't know what it was for originally. Most of all, I don't recall ever seeing one with the long threaded post like this one has. I was going to use on my project, but maybe somebody else might have a better need for it.

It's marked "USC" in a circle on the back. The terminals are marked "Rad. Coil", which I ***ume is radio & coil; "AM" which is probably ammeter; and the long terminal (about 1" long) is marked "GA" (???). It's also got a patent number which shows the patent was taken out in the 1939/1940 era.

Anybody know what car this switch was intended for and what "GA" means?

Thanks,
-Bob

 

It is a Chrysler product (Dodge, Plymouth, DeSoto) from 1943-1948. You can tell it is Mopar by looking at it (keyhole, face) however I visually compared the grooves in your keys to a book i have to find the years it was used.

Hope that narrows it down a bit....

 

Thanks for the info, I appreciate it.