This bulletin applies to 2013 Honda Fit vehicles equipped with A/C. If the left dashboard side vent is warmer than the right side vent with the A/C on chances are the evaporator core isn’t being flooded with enough liquid refrigerant, causing it to fully vaporize halfway through the core. As a result, the side of the core with some refrigerant (the right duct) stays cold, while the side that’s fully vaporized (driver’s duct) is warmer by about 20 degrees F or more.
The most likely cause for this problem is a low refrigerant charge, possibly due to a leak. Another culprit might be a restricted line or component that’s cutting the flow of liquid refrigerant.