Unit in attic working outside unit not coming on i can push contactor in and it will come on

That buzzing sound is the contactor chattering needs to be replaced it is sticking that is what shut the outside condenser off.

Sounds like you are on the right track. The symptom of the contactor not pulling is your clue to the solution. When you turn the thermostat down lower than the room temperature and the thermostat calls for cooling, the outside unit should start immediately. There are a few exceptions to this but generally this is correct. So if you turn the system to cool and the thermostat is calling for cool then the contactor should pull in immediately. If it does not then check for 24 volts to the contactor. If you have 24 volts to the contactor then the contactor is the problem. If you do not have 24 volt power to the contactor coil then you will have to find where the break in voltage to the contactor is happening.
There are many reasons why you may not be getting 24 volts to the contactor, so check what i stated above before you go any further. Repost if this is the solution or you need further assistance.
Important tip....the yellow wire from the thermostat carries the 24 volt power from the thermostat to the contactor.

could be a thermostat problem but even more likely the contactor on the unit outside is stuck. In order to change this part you will have to get in to the outdoor unit. The contactor is the automatic switch that the thermostat energizes when the thermostat calls for aircond. The location of the contactor is in the outdoor unit (electrical section) and where the power will tie in to the unit. It is a little box looking part with terminals where most of the wiring connects. If the contacts are welded together the outside unit will not shut off. If you tempt to replace this part, make a diagram of all the wires connected to it before you take any of them off. Turn off all power to the outdoor unit before inspecting.

first you need to make sure you have 240 volts to outside disconnect adn then at the contactor on the outdoor unit coming into unit..after you confirm is the contactor engaging when the call is made for it to come on..it requires 24 volts to engage the contactor and you should see wires coming to the side of the contactor ..you can manually push it with caution this is electric and it should come on if you have power there. if it is not coming on without assistance you have lost 24 volt power to th eoutdoor switch,,,,,some units do have reset button usually down low near the copper pipes on the unit...it usually is red or green in color...

Check your disconnect or breaker that is located close to the outside unit. Next you need to check the contactor in the outside unit. Set the thermostat to make the air come on then check the contactor. It should be pulled in closing the contacts. If it isn't the problem could be the contactor or thermostat. Next check the voltage on the load side with it pulled in. If that's good then check the capacitor. If it looks swollen, it's bad. You can also use a multimeter with the capacitor check function to do this. Let me know what you find.

I assuming that the black box is a 100 amp breaker, which is connected to your condsensing unit (outside unit). If you open the box and pull the fuse then this will turn off/kill the power to your unit. As far as the buzzing noise it could be that the contactor is engaged. Hopefully, your fan motor is burnt out or the capicator is bad. If you take the access cover off and check for voltage at the contactor you should know if it is the fan motor. The voltage will come in at the bottom T1 T2 T3, once the contactor is engaged L1 L2 L3 will have the same power. Of course if your contactor is not engaging then thats the probelm, you can manual engage the contactor by pushing it in. There will be four wires two running to the capicator and the other to the contactor, these are the wires that control the fan motor. The other three wires run to your compressor. Hope this Helps Tim

You will have to find the contactor which is located in the outside unit. And check the voltage at the contactor, 26 v as this is the thermostat calling for the compressor to come on. You can also push in the contactor and see if the fan and compressor start. There should be an outside fuse box close to your condensing unit. Good luck

If you were able to check the voltage, did you check to see if you had 24volts at the contactor? Did you
have 220 volts coming into the contactor? If no to the
first question and yes to the 2nd question, take a
insulated screwdriver and push the contactor in, the
unit will run. You have a low voltage problem.

2nd, do not reference the 220 volts to ground, if you
dont have 220volts feeding into the contactor,
example read voltage between L1 and L2.

The attic fan is not a part of your a/c system, and you should not run it while you are running the a/c. If you are currently using the attic fan, it is possible that someone wired it so that the a/c won't turn on while the attic fan is on. Otherwise if the thermostat is set below room temp, and says it is calling for cool, then the problem is most likely coming from an issue at the outside unit itself. Make sure to check your fuses, at the fuse panel and outside breaker. Hope this helps

FYI.. the only part of the system that might use batteries is the thermostat.

CHECK THE COIL ON YOUR CONTACTOR TO SEE IF YOU HAVE 24 VAC
CHECK YOUR BREAKERS MAKE SURE THERE NOT TRIPPED AND LET ME KNOW