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Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need. Please be patient as many times we work with several customers at once.
Could be a bad thermostat. Have you tried bypassing the thermostat?
To bypass the thermostat, turn furnace or air handler power off, take the front section of the thermostat off the wall, loose from the back section (called subbase). You will see the thermostat wiring. Take the red wire on R or RC-RH, yellow or blue wire on Y, and green wire on G and twist the ends of these together. Then power back on. See if A/C now runs.
If fuses are good and no tripped circuit breaker, then you either have bad wiring from inside unit to outside, or the unit is locked out on a low pressure switch or timer. Get a voltmeter and check across the two low voltage wires that come from inside to outside unit for 24 volts AC
There would be two wires that go from inside unit to outside to activate contactor. This is where I want you to check for voltage.
I have to leave for a bit, but will check back later when I return
If you have thermostat jumped as indicated above, then you have bad wiring somewhere.
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