My outside air conditioning unit does'nt come on. What could be the problem?

Question

It does have a humming sound when turned on.

Answer 1

the humming sound is probably the electric contactor trying to grab-if so, that's what's bad. you can manually press it in to get the unit to run, but once it stops it will let go again-it's a relatively cheap fix.

Answer 2

The humming sound is most likely the contactor.  This runs on 24 volts from the thermostat.  Check the circuit breakers inside the house.  Air handler runs on a different breaker.  Also check the disconnect next to the outside unit.

Answer 3

Your run capacitor is probably bad. Disconnect power and take off the panel where the elect. wires are. Your capacitor looks like a tin can. If it is blown out on the top or bottom[like a frozen coke can] then you need to replace it. If that is not the problem, then it is probably a relay gone bad. Good luck.

Answer 4

make sure that the thermostat number on the air conditioner is lower than the inside temp.

Answer 5

It might be that the blower motor burned out.