2.25 keeps running after I turn the key off.

[NC_Mule]

1970IIA 2.25 gas RHD
At the post office the other day and I turned the key to the off position, removed the key and the engine didn't shut down. I just left it running since I live in a small town and theft is not an issue. Drove home and figured out that the engine shuts off when I move my headlights from the running light position to off. The truck starts fine with the headlight switch in any and all positions.
Looking at a wiring diagram I only see one wire that goes from the headlight switch to the ignition switch. I pulled the dash and inspected that wire and cleaned all the grounds behind the guages. Everything looked in order.
Tested the truck and the problem seemed to be fixed, the key shut the engine down like normal.

Four days pass and the problem has resurfaced. Not very familar with ignition switches, what actually happens when you switch to the off position and the engine stops? I assume the ignition circuit is opened somehow.

thanks for the thoughts and feel free to ask questions if I can clarify something.

pb

[I Leak Oil]

Turning the key to the off position simply cuts power to the ignition coil. Sounds like you have a bad switch.

[NC_Mule]

Any thoughts on why killing power to the running lights cuts the coil off?

[NC_Mule]

New switch is a wopping $18.50. Guess I'll give it a try.