Ac won't turn on it just clicks.

Question edited for clarity.
Question moved from AC Cars (sports car called AC Cobra)

Turn off at the breaker for 1 hour. Then turn back on and wait 15 minutes for it to do its self testing.

If that doesn't fix it, you need LG service for the Outdoor Sensor.

check for a problem climatic control unit
if the ac gave out cold air when the thermostat was adjusted , it indicates a control problem rather than an ac problem
take it to an accredited ac specialist shop for a proper diagnosis and quote

pull out the plug or just turn it too off for 20 minutes and plug it back in/turn it on. when power goes off the compressor will click and keep trying to restart. this also happens with AC s turn off and let sit usually fixes most of these

there is a fuse on the circuit board on the inside unit. Typically a power surge will pop it. checking that fuse is the best place to start

You can try a new AC adapter.If that does not work,it will need to be repaired by a Nintendo authorized center.(I used to work at one).If you do by a new one PLEASE buy Nintendo brand.The "off" brands usually end up in some kind of problem down the road.
Good luck and agme on!

-AC means no power to thermostat from furnace.

I found a paritally blown fuse. When the fuse blew metal pieces ended up partially making contact. After replacing the fuse everything worked great.

Let me see if I understand your question.. your thermostat indicated the batteries needed to be replaced so you changed them with new ones.. With new batteries, you cannot get your thermostat to initialize or program correctly and as a result of that, you cannot get your AC system to start up.. If that is true, please provide the Honeywell Model # and verify the batteries you installed were Ok,...
Will attempt to assist once you've provided this info..

( on an off chance, have you checked the fuse or cuircuit breaker for your AC system to make sure it has power available?) This is especially important after a power outage..

Blank screen sounds like a fried thermosat. Abrupt outages can affect certain types of thermostats. Make a jumper wire and jump across R and G. See if you get any action from anywhere. If a fan or compressor kicks in you know you have a burned out thermosat...

is this a whole house air conditioner ,
if so check the fuse panel,
check to see if the outside unit runs at all , compressor or fan.
check the ac transformer power to the thermostat
check the switch in the ac closet
doe the internal fan run if you switch to fan only.