I,ve got a 3 ton trane split ac unit with a variable speed fan motor on the condensing unit.I,m Not sure which component is defective. I,ve replaced the outdoor fan thermostat switch which was bad.(sometimes it would close,sometimes it wouldn't.Switch has a close in /out tolerance of 76-80f.Can someone tell me how to check tke fan contol boad (the one with the red led) and the fan motor to be sure I have no problems there. Installed in 1992,model# TTY036A100AO. Any information about this design would be appreciated.To me it seems like a headmaster setup.Could be a servo motor for all I know.I'm green as a gourd and still learning.Thanks, my hat's in my hands.