If I recall right , MB has 2 different rear ACs. 1 is tied into the front AC compressor, the other has its own engine driven compresser. I got a much better, aftermarket rear AC, (
They are an MB approved upfitter) Proair
http://proairllc.com/condensers.html (I have the 941) (they have approved shops to do installations around the country)Mine was installed by a shop thru SMB texas. I didnt want the MB, as its roof mounted ,you have no choice in where its mounted and its placement may mess up your plans for conversion,... and I needed the roof for my 110AC , solar panels, maxi vent, satellite . I have a few friends that had the 110v Danhards and where not happy as they dont have as many BTUs as the 13,500 BTU or 15000 BTU roof mounted 110 ACs and could not keep the 170wb sprinter cool when parked in summer. Mine is a coleman 15000 btu