1999 grand cherikee dual heating zone 1 side hot passanger side cold

check temp. blend door actuator its what controls the temp doors to change from hot to cold usually pass. side door breaks on jeep grand cherokee's causing pass. side to be cool,have seen some on drivers side break but not as many

My 02 Century has dual temp controls . One for driver for passenger. Make sure you don't have the dual climate enabled and just set for heat on your side and AC on the passengers

ummm...well first try to flush your radiator and put some new antifreeze and hopefully this solves the problem but when yuh put new coolant let it run for like 20 mins...

may have a bad blend door actuator.

junk it its not worth it one of the sensors that open and shut the door are bad

U will need to replace the pass side air temp control blend door acuator motor.

have you checked the coolant level on the car to make sure its full?

Well lucky you i just fixed one of these jeeps at work. I take it that there is dual zone control one the jeep. First off its a 6 hour job you have to remove the entire dash and heater control unit. On the back side of the heater control housing there is a small motor that controls a heat blend door i found the motor to be ok but the door was broken. if you go to you're dealer they have a new updated door and a few other pieces you have to put in also. Also if they check the computer codes there will be a few codes im sure . I woul dleave this one up to the pro's but if you wana try it let me know.

Go to heatertreater.net. I bought one for my jgc and now it's working great. It's the blend doors that are broken. My has dual temp controls but it still worked for mine. The only thing is, the passenger side heat and air temp stays the same as the driver's side. Who cares!!!!!! It's warm and a whole lot cheaper than what the dealer costs. It took approx. 1 hour and $120.00 for the part. I paid $20.00 extra for express shipping. It's getting cold in Tennessee.

http://www.fixya.com/cars/t954198-99_park_avenue_blows_cold seems like same problem. Hope this thread helps you narrow it down