penn station posted:...
Note, if the switch is OFF and you run an engine into the siding the LED will illuminate.
cjack posted:...But the Calterm 40393 does not short the load to ground. It's truly an spst. I would still measure with an ohm meter, but the 40393 switches I have do not short.
The two automotive switches shown in the OP's photo are sitting right in front of me. With the switch in the OFF position, applying 12V DC to ACC and GROUND do NOT illuminate the internal LED!
So these 2 behave like a DPST switch. Perhaps like this:
If you have one of those Calterm switches lying around, you might try applying 12V DC to the ACC and GROUND with the switch OFF.
So perhaps there are different variants of these automotive 12V DC illuminated switches. I don't know the fine details about automotive electronics, but I can imagine an application where you want to "short" the load when the switch is OFF...say if driving a DC motor this would rapidly stop the motor by shorting the windings and also eliminate the large potentially damaging voltage spike when instantly removing current to an inductive load. Again, this is conjecture based on ignorance!
