couch switch shuts off when ignition is turned on

[oldgoatwinery]

I have a '93 Coachman Santara, Cumming 190hp diesel. When I put the coach switch on and turn the ignition key, the coach switch shuts off and prevents the engine from starting. Coach switch lights back up when key is turned off. Coach & chassis switch is a year old. New batteries, all battery connections and grounds checked and cleaned. HELP!!

[1492]

Moved from Forum Technical Support

[ScottG]

FYI, "Cumming" S/B "Cummins".

[Chris_Bryant]

Something is miswired- the coach disconnect should have no affect on the chassis side. New batteries = opportunity to hook cables up wrong.