RVP Thermostat 8330-386 Question

I have a Coleman 8330386 Digital Thermostat purchased 2 years ago as a replacement to the original of the same brand and model. This new one is failing to work properly. If I turn the fan on only, it will run with no issues on both LO and HI setting. When I turn to Cool the entire unit shuts down after a few seconds and will not cycle back on no matter how low I set the temperature. The heat will not turn on at all even with the temperature set to 88. I feel like this is a faulty thermostat, but wanted to ask because this is the second one to go bad and now looking to purchase a third. Any help would be great. Thank you.