About a year ago while going on a family vacation, my front and rear ac started going warm. We left the Traverse with my Sister-N-Law who drove it with the ac on. After returning from our paradise vacation, we left the sister-n-law's house to return home. Two hours later we made it home with the compressor bearings grinding. The next day, the compressor stopped working. I had an extended warranty that covered the compressor and the 134A refill, but not the new front ac line they installed. After the fix, cold air blew from all vents, front, back, and seats and slowly over a years time, it warmed. Last week, the back vents did not get cold, and the front no longer blew cold air like a year ago. So, I got my thermometers and placed one in the from center vent, and the other in one of the rear vents. The front vent read 60 degrees F, and the rear 110 degrees F. I decided to check the rear actuators. The floor/vent worked well. The hot/cold worked well. I put the rear back together. I drove for a week using the front ac to cool the entire compartment which it did. Today at 92 degrees F, I felt like investigating. I let the Traverse run for 10 minutes with front driver and passenger temperatures set to 60, fan high, seats cold, fan high, rear ac, cold, temperature difference set to 0. If it is 92 degrees I thought, I want the air to come out of the vents at 52 at least. So, I added the refrigerant until the front vents got around the desired temperature. The rear vent temperature is the major problem. It read 110. I jacked the Traverse, took off the plastic wheel well shield and felt the ac lines. The largest one was cool. I took the inside 1/4 panel off, and disconnected a vent to access the evaporator. With fan off, I put my hand inside to touch the evaporator, it was cool. As the engine ran with front ac still set to Antarctica, the refrigerant finally got the rear ac line cold to the point it started sweating. But, as soon as I turn on the fan, the evaporator warms, and so does the line. I am thinking there is a leak somewhere. I am thinking I need to check the front of the system to the back, especially that rear evaporator. So, I am continuing my trouble shooting with ordering a cheap refrigerant halogen leak detector to see what it reveals. I will keep you posted.