I have a 4 year old Kenmore Ultrasoft 425 water softener that just recently has stopped working and displayes error code Err3. I have gone through some of the troubleshooting diagnostics in the manual with out success. I think I have narrowed it down to the valve position being the problem but am unsure of what could cause it... The switch or the actual PWA. I can see the switch indicator opening and closing as the valve rotates however the valve position indication always reads Serv. I never see it toggle between the other modes (Fill, Brine, Bkwash & Rinse). Any insight would be much appreciated.