Sounds like fan is clicking on roof top dometic RV ac unit, but fan is not hitting anything.

SOURCE: duo-therm by dometic ac rv unit

I suspect that you have a bad selector switch for the on, off, low fan, high fan operation. If the selector switch is put into the off position everything should stop completely.

SOURCE: ATWOOD MOBILE FURNACE RUNS WHEN IT WANTS/

Check your furnace for power. will be 4 wires. power ground and 2 thermostat wires. Check for power at the time delay relay, if you have power there check for power going in the fan motor, if power in motor wire, motor is bad. If no power in motor wire and power going to circuit board take the 2 thermostat wire apart and wrap the 2 together comimg from the thermostat. Fan will stat in about 30 seconds. If it does you need a control kit in the ac. But sounds to me like you have a furnace problem.

SOURCE: How do I clean out the vents in my RV Dometic roof

Take it off,the plastic inside vents, with soap water and a hose wash it.  Outside condendor and inside evapator, making sure the drain is open and outside shroad removed, brush off fthe loose stuff. wet both units, put liquid dishwashing soap on both. Spray then through , with a hose untill they rince clean.  While up there. Oil the motor if possible.  Keep the drain clear and open,making sure none of the water is getting into the RV.

SOURCE: FAN SHUTS OFF BUT COMPRESSOR KEEPS RUNNING - 6 MONTHS OLD

Depending upon the model of your air conditioner, this may be normal operation.

My newer Dometic air conditioner will run the compressor in a "reverse" mode without the fan occasionally in order to heat the coils. This is done to defrost the coils. After the frost is gone, the fan switches back on and everything goes back to normal.

SOURCE: Fan does not run. Low power hum audible.

sounds like you have a bad run capicitor on your fan check if the cap is swolen and or any oil around the terminals thats usualy a tail tell sind thats its bad