big jam switch near brake booster

[navion]

So what is this larger jam switch for. Its about 1 inch in dia. and has open contacts when the hood is open , closed when the hood is closed. I think thats the configuration. I know about the "jam" switches for the under hood lights but this one has me puzzled.

[bradartigue]

What year is it?

This is probably not a jam switch, but the set-test switch for the fast idle solenoid.

[bulldog4444]

Sounds like the brake fluid low/test button. Spade terminals 180 degrees apart and a LARGE button for test. Turn key to acc. and see if the dash light works when pressing. Good luck!