Turn on the heating system. You should hear the system turn on. Air should start to blow through the vents into the RV. If the blower will not turn on, check the voltage at the furnace with a voltage meter. The furnace requires a minimum of 10.5 volts to operate.
Check the 12-volt DC fuse. If the fuse is blown, replace it.
Check the battery cables to ensure they are not reversed. Reverse polarity will prevent the heat pump from turning on.
Check the thermostat for open contact points. Close the contact points with a screwdriver if necessary.
Check the blower motor. Turn it by hand to verify it is not seized. Replace the blower if it cannot be turned by hand.
Check the motor relay. It is an electrical switch that controls the flow of electricity to the motor. Replace it if it is not working.
Replace the motor if steps 1 through 6 do not resolve the problem.
Check the voltage of the RV battery. Low voltage can cause noisy operation of the RV heat pump. Charge or replace the battery to correct this.
Listen for a metal on metal sound as this is indicative of an unbalanced blower wheel. Replace the blower wheel to correct the problem.
Check the blower wheel to be sure it is properly tightened. Tighten the wheel if necessary to correct the problem.
Listen for the burner to turn on. If it is loud, adjust the air shutter so that the correct amount of air flows through the system.
Check the clearance in the housing of the blower wheel to ensure that the wheel is not rubbing against the housing. Adjust the clearance to correct any contact between the housing and the blower wheel.
