Check to see that the Carrier air conditioner's power cord is connected to power. It is a simple, often-overlooked fix. If this is the case, plug the air conditioner in and turn it on.
Check the circuit breaker to see if any fuses are blown. A fuse may be blown or need to be replaced.
Check the connections to the power and between the roof and ceiling on the Carrier air conditioner if the fan is running too slowly. Loose wires could cause this problem; if this is the case, just push the wires in or tighten the connections with a wrench.
Use a volt meter to test the voltage on the battery if the unit's fan is running slowly or the compressor isn't running. If the voltage is below 10.4, you should plug the RV into shore power.
Clean the condenser with canned air or mild soap and water solution if the condenser is clogged or dirty. This problem could cause the compressor to constantly run.