0 Members and 1 Guest are viewing this topic.
There is a reason the compressor engages with defrost...part of the reason is to dehumidify the air that is blowing on the windshield. This isn't that important for "defrosting", but if you live in a very humid area, it is essential for "defogging". My ac leaks freon like the Valdez, so I am not able to take advantage of the dehumidifying of the air blown on the windshield, and it makes defogging the windows a pipe dream. The other reason for the HVAC to function that way is to keep the compressor for sitting idle for months at a time. If there happens to be any moisture in the system, it can settle in the compressor and start causing corrosion/rust. Cycling the compressor with the Defrost function keeps the moving surfaces of the compressor lubricated and any possible moisture suspended and not settled out causing corrosion somewhere. If humidity isn't a problem, then the defrost/defog may still work as designed, but don't be surprised the first warm day of spring when you decide to kick the air on and get the belt scream of death from your compressor.