[Richard]

You are not going to like my response. While at the rally, I was going through the whole deal of checking out the ac systems on a new to me coach. I pulled one of the SCS units to get to the air return plenum. One of the units had some sort of black spooge adhered to the coils that soap or coil cleaner alone would not touch. I could only remove it by running a coil comb overs the fins. I suppose it was a mixture of very fine dust and grease. Yep it was a nasty wet job to crawl in the plenum and clean the unit. Of course the one I removed was the easy one to clean.

Not saying that removing it is a must, but if the coils remain black then they are still dirty. The internal coils are silver.

More info that may help you. At 85 degrees ambient air temp I get 54 degree air from the front unit and 63 air from the rear. Also the rear cools two thirds of our coach and the front cools the forward third. Given the location of the thermostats we found the setting the rear three degrees lower than the from helped with overall temp distribution. I thank Ashley and Forest for that tip