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Based on your description we may have either a faulty valve or module and in some cases the valve can short out the module. The valve can be mechanically stuck or if the valve loses the power or signal it will default to fully open. If you have NAV the climate control module is the remote module mounted behind the glove box. The module is most likely not energizing the valve closing it off preventing hot coolant from entering the valve. The good news is that we can test everything at a connector located behind the left hand side dash panel. If you have a voltmeter we can test it.Go to the left side dash and remove the side panel. You will see some connectors. We are looking for the green connector. Use a light and you will see each wire pin numbered. You are looking for the 14 way green connector. Make sure the key is off and disconnect it. With a voltmeter check for power on pins 9 (brown/green) and pin 10 (brown/white) on the harness side you disconnected. If power is present then leave the black lead of your meter to ground, reconnect that harness connector to the dash then start the engine and turn the climate control to full a/c. You should read low voltage on both pins and you should see it change as you increase/decrease the temp on both pins. If the voltage stays high you have a bad module and the valve was most likely shorted.