The CLICK is a relay. powered by 12 volts. IT turns on the 120 volts to the Blower and compressor.. SUSPECT #1 and 2 is the circuit breaker feeding the A/C
1: tripped
2: many RVers have a few screws loose. One of the circuit breakers on my power box took over THREE full turns before the A/C hooked to it behaved.. NOTE there are also bus bars in that box check those too.. NOTE 2: Make sure the power is off
3: If you are on 50 amps. the park power or the RV may have a tripped breaker one side of the 50 amp pair or I've had a wire come loose in my plug costing me half the RV power wise as well.> I fixed it.