I have a Trane XV90 unit. The unit is not coming on. The condenser comes on, the thermostat is working well indicating the room temperature at 86 degrees, and programmed to cool at 75 degrees. The '*' is displayed on the thermostat indicating that the unit is on cool.

I opened the panel to check the error message: The Red Led flashes every 20 seconds; while the Green Led flashes steadily every second.

Is there something that needs to be reset?

Turn off the breaker in main box that goes to the furnace,, wait a few minutes and back on,, see if this helps

There is no reset for a capacitor that I ever heard of