Oly fan will run on low and high on manually only. Switch to automatic cooling and nothing runs. I have checked lo and high voltage on this unit and the 2nd ac unit on this RV that is working just fine. I have changed out the printed circuit board along with the starter unit and also the freeze sensor. My middle unit still wont work but the front unit still works just fine even with exchanging all the components. Only thing I havent switched yet is of corse the compressor and fan assembly.