How do I fix a thermostat that will not start my A/C?

Answer by  eyeguy (3760)

The entire device should be replaced , if you have tried starting the system in its auxillary or emergency mode with no results.

Answer by  Noah77 (37)

This depends on the type of thermostat you have installed. Non-dgital thermostats have no parts that can be repaired and should be replaced. Digital thermostats can't be repaired either but have settings that can be changed. Follow the thermostat instruction book to see if your thermostat is set with A/C enabled. If A/C is enabled replace the thermostat.

Answer by  squintz (92)

First verify that the problem is with the thermostat, and not that A/C unit. If the A/C unit works, check the breaker for the thermostat. If its fine, replace thermostat.

Answer by  HUNM25 (713)

Well the first thing you want to do is consult the manual that came with your thermostat. It could just be possible that your A/C feature has been disabled. So look in the book to see how you can enable it.

Answer by  AbbieThompson (175)

First, check the continuity of the thermostat wires. They are very often chewed in half on the outside. If this fails, uninstall the thermostat. Then, when reinstalling, make sure to match the wires color to color. If the last attempt fails, the thermostat is broken and will need to be replaced.

Answer by  kipcat (1964)

the thermostat is rarely the problem. The thermostat is a low voltage device that picks up a contactor for the high voltage compressor and fan. Call an electrician.