Temperature blend and recirculation doors commonly fail, which can cause the AC modes not to change or the temperature to be different on the left and right sides. If replacing blend air doors, a recirculation door, a door link, or a sub-assembly housing, new heating, ventilation and AC (HVAC) sub-assemblies are available that improve reliability.Google+
Car Problem Reports
Jeep Grand Cherokee Temperature Blend/Recirculation Doors May Fail and Cause AC Problems
Jeep Grand Cherokee Problem
Average Mileage: 103,799 mi (12,000 mi - 250,000 mi)
Hey Guys... If you are getting NO air through the ducts and the fan is on, it is probably the recirculation door behind the glove box. Mine broke and fell to block any air coming from the fan. Easy, cheap fix - I removed the glove box, used a wood shish kabob stick to lift the door back into the open position then used wire to secure the stick to the plastic grate covering the cabin air intake. I now get great air circulation.
If there is a problem with temperature control and/or differences between the passenger and driver sides, then it is probably the blend doors. Mine broke too...
Visitor, 2002 Jeep Grand Cherokee, 109,300 mi
I had the blend doors and recirculating fan replaced 3 years ago. I have experienced a heater /ac problem again. i installed new blend doors and that did not correct the problem, the old plastic blend doors were still good. I have noticed the blower sound like it is on but no major air flow comes out of the vents, not to mention no heat. what may be the cause, im lost .
Visitor, 1999 Jeep Grand Cherokee, 166,000 mi
My air flow through air registers would not change. It was always on the defrost mode. Found the VACUUM hose not attached on the intake manifold side. Connected the hose all systems back to normal. (vacuum hose located on the driver side under the hood) Check the intake manifold there should vacuum hoses connected to the intake manifold. There is also a diagram and a notation under the hood. When you open the hood this information is on the underside of the hood (front end)
Visitor, 2001 Jeep Grand Cherokee, 182,000 mi
AIR DOES NOT COME FROM ALL VENTS, MOSTLY COMES OUT FROM FRONT WINDOW DEFROSTER
Visitor, 1999 Jeep Grand Cherokee, 100,000 mi
Heat on the pass side cold on the driver side....quoted $1500 to fix. $500 for parts, $1000 for labor. I feel like I could fix this myself but not sure how hard it actually is or the steps that need to be taken to avoid causing more dammage.
Visitor, 2001 Jeep Grand Cherokee
cold on passenger side when heat is on!!!
Visitor, 2001 Jeep Grand Cherokee, 126,000 mi
No Heater, no hot air blowing after temperature is raised.
Visitor, 2001 Jeep Grand Cherokee, 122,000 mi
pass / side cold air drvr's side any temp you wanted. found out dlr weanted $ 1300 plus estemated. jcg.com sells kit w/instructions did it myself for 150.00.
Visitor, 1999 Jeep Grand Cherokee, 130,000 mi
right side air is always at the coldest. no heat on the right side and air temp will not change, left side works good.
Visitor, 2001 Jeep Grand Cherokee, 105,000 mi
cut a hole put a screw in to hold them in place for winter