Rear climate control box #15-75306
There is a controller box in very rear passenger side (part #15-75306) that is common to fail. Parts under $50 & simply installs by (remove HVAC fuse under hood first) removing black tie down knob in very rear, 1 small bolt & a clip pop in, then working up rear plastic floor kick panel about 1\2 way across then popping out lower part of pillar (upper back corner). You can then prop up the side panel (careful of pulling off cig lighter outlet wires) plenty to get access to remove the controller (2 screws & 2 plugs) then simply install new. Leaving the fuse out start the vehicle & let run for 60 seconds then shut off, replace fuse under hood & start again. Give truck few minutes to warm up & you're good to go. You can remove the whole rear panel to get full access but not required. This fixes your problem over 90% of the time. Just did this last week, took 15 minutes in driveway & fixed same problem for me.
Hope this helps anyone who's rear climate blows only cold.
