[rwg200]

Good find Richard.  Nason has been a supplier of pressure and temperature switches to many companies including Cummins prior to Cummins's purchase of  Onan.  I don't recall having any issues with Nason on Cummins sets (prior to the Onan acquisition)  or the hundreds I've built.  The switches furnished by Kubota and Yanmar are not Nason,  the Nason switches on PT sets have been installed by PT as far as I know.

In Rob's case the switches all go to ground, if he lifts the wire from the switch he will eliminate that switch's function.  The exception is the fire extinguisher,  it is in series with the hold-in coil.

Thanks Richard for your diligence.

Thanks for all the help on this, i will be back with the coach next week so will start to try and work through the suggestions! 
thanks again,
Rob