SC 4000 or 4500? If SC 4500, then view the switch "input" via Access 1 "Analyzer" mode. Disconnect wire that attaches to Reverse switch. If input says 1 ( switch closed when it should be open), there may be a short circuit within Access 3 module.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.