My switch is an ON/OFF switch that controls the solenoid, but my solenoid is different then yours.
The system you talking about is frequently called the Salesman switch, which turns power off/on as you are entering or leaving. In the short term you can simply connect the two large wires together and then use your main battery disconnect to shut power off to the coach (which is a good practice if you are leaving it for any length of time).
The switch you mention is a Carling switch, you should be able to contact Carling to get a current part number that will work. Or contact NWRVSupply
They carry a good selection of switches and have one.
I'd replace the switch first.