Emergency Start Switch

[BronxtoAustin]

I recently purchased a 2005 B Touring Cruiser on a Chevy Chassis. I found the emergency start switch cable was disconnected from the chassis battery, but still connected to the house battery. When the engine is off, there is no voltage at the chassis battery cable until the switch is depressed, this appears to be operating as it should. However, when the engine is running, I am getting full voltage through the chassis battery cable. I am wondering if this is normal, or if the previous owner disconnected it for a reason.
Thanks.