1999 Jeep Grand Cherokee Heater Trouble

My 99 grand cherokee’s heater is broken - fan blows but only cold air. I’ve had two mechanics tell me its probably the blend doors and will be quite expensive to repair because it requires removal of dashboard. Does anyone have any experience with an after market repair kit which allows for a DIY fix going through the glove box? Is this a good bet to try? I just can’t invest $1400 to repair.

The first thing I would check is to see if there is a water control valve in one of the heater hoses just before where it enters into the firewall. The heater hoses are about 1" in diameter and two of them enter the firewall, under the hood, about an inch or two apart.

If one of those hoses has a valve in it, there will be a cable attached to the handle of the valve. Have someone mover the heater control on the dash and see if the valve moves. If it doesn’t, it may simply be disconnected in the heater control panel or at the blend door on the bottom of the HVAC vents, easy access.

Taking out the heater control panel can take an hour or two so that might run a couple hundred.

More than likely there’s a problem with the blend door actuator.


The blend door actuator controls whether hot or cold air comes out the vent system. The blend door actuator is replaced by removing the glove box.


The shaft on the blend doors break on the WJs. There is a bulletin for revised blend door housings and recirc. door housing.

When I worked for a Jeep dealer I replaced one per week, takes 3-4 hours. The labor time is only 4.8 hours plus reclaim/recharge of the refigerant so you should be able to get it repaired for a lot less than what you were quoted.


If you go on Youtube and enter in their search engine, “99 Cherokee blend door actuator”, you’ll see how the shaft can be replaced by removing the glove box.


That is one way of getting the vehicle back on the road but it isn’t pretty. Damage the heater core and your back to square one.

Personally I’d rather replace the housing, I’ll bet I could replace the housing faster than a DIYer could cut the box up like in the video.