I, like many have replaced a couple of fan motors and capacitors over the last few years. When our rear unit quit putting out cold air, (it was probably the valve that switches it from air conditioner to heat pump), we decided it was best just to replace the two 18-year-old units. The new 15 kbtu heat pumps are almost $2,000 a piece now. But the idea of being on a trip and an AC unit going out again convinced us the replacement cost was justified. Talin RV is doing the work for us right now. Talin indicated a aftermarket thermostat could void the warranty on the units, so a new 10 button dometic is also being installed. Although it's expensive, I decided it was best to replace it all, have someone else do the work, and know that it's all done right so that we can enjoy using the RV instead of working on it!