Have a 2007 Winnebago Voyage with Basement HAVC . when I turn on the A/C the fan comes on but not the compressor , just had he circuit board replaced 5 months ago . hate to have to take it back to the...
Does the compressor attempt to start? If so it may be a start capacitor. Less than $20 and a simple fix. If it doesn't attempt to start it could be the control board, which you said is new, or it could be the relay. The relay is also an easy fix. Open up the unit, swing up the compartment door and remove the panel from the front. Turn it on and look at the lights on the control board. They'll give you a clue as to what the control board thinks is going on.