Re: 04 Mountainer Rear Auxillary A/C Evaportor Core Question
If you look under the hood at the compressor you should see two lines exiting; one for the front AC and one for the rear. If it's anything like my Durango with dual AC, the compressor still charges both lines at all times. Only if you had a dual compressor setup (not on light duty vehicles) will you truly be able to shut the system off. The 'off' switch you mentioned only turns off electrical power.
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!