2008 EZGO TXT 36 Volt Golf Cart Shifts from Forward to Reverse on it's Own?

[lstill]

Hey guys have 2008 36 volt EZGO TXT golf cart. They had removed batteries and was unsure of condition. Replaced batteries, nothing. Started by inspecting Curtis controller, (removed top and had obvious water damage internally). Bought a used Curtis controller and solenoid switch and installed. Wouldn't go so checked reed switch its not an issue because its been bypassed ran 36 volts to the yellow wire on solenoid, turned switch to run and wala ran great in forward position but nothing in reverse. I then purchased a new forward /reverse switch hoping this would alleviate the problem but didn't help. The next day ran the cart again and this time in forward position it went in reverse....? Turned off and back on this time it went forward with no change in switch position. I'm starting to think a used controller may have been a bad choice. Has anyone ever heard of this happening. I know that there is power to and thru the switch the forward and reverse switch is brand new. My thoughts internal fault with controller. Any thoughts or suggestions appreciated... Larry