blower turns on, but not the condenser

(Massachusetts)

When I turn the central air conditioner On I can hear the blower come on but it just blows hot air. Out side the condenser unit doesn't come on.

I checked the Circuit breaker but it appears to be fine. What else could I check? The Thermostat is Honeywell (round). It's 1 year old and the central air conditioning unit is about 5 years old.