"Why does my Jeep's heater only blow cold? Why is there heat on only one side in my Grand
Cherokee? How do I fix my heater?" If your Jeep Grand Cherokee heater only blows cold on one
side all of a sudden, or seemed to just quit producing heat one day - you most likely suffer from
blend door failure.

Blend doors are small airway control doors that move into positions to blend hot and cold air to
your liking based on where you have the temperature setting knobs positioned. These little plastic
flap doors hide behind your glove box in your A/C system's housing, and move up and down to
pass heat or cold air as you command.

The material has caused them to be weak and brittle allowing them to fall apart leaving you with icy
cold air as the only option. That's fantastic if you live in Florida or Arizona in the summertime but for
the rest of us we are going to need our heater.

Take a few moments to watch the videos and dig through the photos to make sure you fully
understand why your Jeep has no heat, and how to fix this common problem all by yourself, right in
your own driveway using only a few simple tools. Complete the final Check List here.
If you are still not sure the HeaterTreater II blend doors will solve your problem - Read on. We have outlined a
way to see if your heater blend doors have failed.

If you have no heat on the drivers side - this test will work for you.

If you only have no heat on the passenger side only, please use the electronic method outlined above.

Please follow the steps below. This method involves a little disassembly but is a great way to ensure our
HeaterTreater aluminum blend doors are the right  solution for you.
How to visually inspect your Jeep Heater blend
doors for failure:



1) Open and remove glove box











2) Locate the drive motor for the heater blend doors.













3) Remove phillips screws securing the drive motor.











4) Remove the drive motor from it's mount. Inspect the
white input shaft at it's base.

Usually a good indication the doors have failed is the
complete lack of a stop limit pin anywhere on the round
base of the white input shaft.







5) Twist the white input shaft counter clockwise (towards
the driver side) and wait for resistance. If the door is
intact, it should stop any amount of force you could
apply by hand. If the shaft spins freely or catches and
then pops free as you turn, the plastic blend control
doors are broken and the Jeep Heater aluminum blend
doors are your answer.
Easy and FREE Self diagnosis for you Jeep Heater
You should now be able to determine if you need new HeaterTreater
blend doors to fix your 1999 - 2004 Jeep Grand Cherokee.
The code numbers will be displayed on the screen one at a time.

22 or 54 – Left temperature door is broken or 47 - motor not responding.

24 or
56 – Right temperature door is broken or 48 - motor not responding.

54-56 are the most common and our Blend Door replacements are exactly what you need to get your Jeep
toasty warm again.

                         
For more failure codes click here
Try this free vehicle diagnosis on you
Jeep Grand Cherokee and see if we
can help. If you see the codes 54 and
56, you are in the right place! Our
JeepHeater aluminum door solution will
restore your Jeeps heat again!


Once all codes have been displayed,
the system will repeat the fault code
numbers. This will continue until the
ignition is turned off. Record all of the
fault codes.
Q: How do I fix my 1999 - 2004 Jeep Grand Cherokee heater that stopped working?
A: Your Blend Doors are broken and need to be replaced.
This is primarily an issue with all Dual Zone
climate control systems in the 1999 - 2004
Jeep Grand Cherokee.

These plastic doors (blend doors) are what
determines how much heat and cool air you
receive when you turn the temperature knob
on the dash. If you turn the knob for hot air,
they move up. If you turn the knob for cool
air, they move down.

These little doors are made of a cheap
plastic that falls apart after a while allowing
them to fall down in the cold air position.
This causes the loss of temperature control
- mainly the loss of heat.

(images) The OEM factory made blend doors are cheap
and prone to cracking. The little drive motors used to
move them up and down are very strong and can put too
much pressure on them causing them to crack, break
and eventually fail. Once broken - your heater stops
working.
Unfortunately it will cost up to $1500.00 and 3 days of no Jeep.

So why does it take so long, and more importantly - wheres that $1500.00 of your money going?

Labor Charges! The dealerships and auto repair centers do things "by the books" and they have plenty of
reason to on this job. Lots and lots of labor when done their way.

The dealerships rules require them to drop the steering column, remove the center console, evacuate the AC
system, pull off the entire dash, drain out the vehicles coolant, disconnect the heater core and disassemble
all of the heater box. That's a ton of work and flag hours. That adds up to big bucks for them. That's good for
the ASE certified mechanics who are getting paid for all that work, but a huge pocket drain for the Jeep owner
who has to dole out all that cash.
Do you have the problem?

The usual symptoms are that one side of the cabin will loose heat, followed by the other side at some point.  

Air Conditioning is working on cold but not hot no matter the control knobs setting.



Limited / Overland :  Grand Cherokee Dual Zone Control

These have automatic zone control and the driver and passenger sides have individual controls.

You can electronically read the
fault codes on the system by following this procedure:

Here's the short version of how the repair is completed using
HeaterTreater aluminum blend doors by JGCParts.

Lower the glove box

Remove the drive motor

Cut a small hole in the plastic HVAC box

Remove the broken blend doors

Install the new
HeaterTreater blend door kit – they just slide in

Replace the piece of plastic you cutout

Replace the drive motor

Close the glove box – Your Done!

It's really that easy! The hardest thing to do is make the first cut.  

This job will take between 30 - 45 minutes for most people.
Choose an option below for more detailed instructions with photos
HeaterTreater Dual Zone blend doors for all 1999 - 2004 Jeep Grand Cherokee.
The easiest, cheapest way to fix and restore heat to your Jeep.
JeepHeater Dual Zone blend doors
for all 1999 - 2004 Jeep Grand Cherokee.
The sure way to fix and restore heat to your
Jeep.
Make the smart choice. Save $1500.00 and DIY
Do you have the problem?

The usual symptoms are that one side of the cabin will loose heat, followed by the other side at some point.  Air
Conditioning is working on cold but not hot no matter the control knobs setting.

Laredo : Grand Cherokee Single Zone control MTC

Our single zone control can be used on ALL 1999 - 2004 Grand Cherokee vehicles! On models with dual zone
control, the dual control feature will be lost.

To diagnose your Laredo MTC A/C System:

There is no electronic diagnosis available for your Jeep.

Physically check the operation of the blend doors by removing the glove box.

Remove the blend door motor which is located to the side of the opening.  

The motor is held in place with two Phillips screws.

Disconnect the wire harness and remove the motor.
You will see the plastic axle that is connected to
the blend door. There should be a limit pin on the
white plastic axle.

The failure occurs because this pin breaks, putting
the force of the motor directly to the shaft of the
blend doors. The cheap plastic shafts can not
stand the force of the strong drive motor and
eventually crack resulting in blend door failure.
That equals a blocked heater core and loss of
heat.

Start the Jeep and turn on the AC.  
Manually switch between heat and AC by turning the axle left and right with your fingers. If there is no change
between cold and hot while turning the white connector, your blend doors are broken and the JeepHeater by
JGCParts is your solution.
Your Choices:

Option (A)

DIY for $150 and about
30-45 minutes using solid aluminum
JeepHeater blend doors



Option (B)

$1500.00 and 3 days later,
that creepy mechanic guy over
there will have it ready for you.
How easy is it?
Fortunately the manufacturer has a solution!
So you're asking - "Can I do this repair myself?" The answer is "Yes!""Rules" are meant to be broken
sometimes, and this is one of them. You don't need to pull out half the front end of your Jeep to do this fix.
You only need a small hole about 4 inches by 6 inches to do the work, and it is all done through the glove
box area.

This is the
HeaterTreater no dash removal, all aluminum  blend door replacement kit for all 1999 - 2004
Jeep Grand Cherokees with Dual Zone temperature control.
The JeepHeater Solution:

Our kit replaces the cheap, brittle plastic doors and axle with high quality Aluminum components. Repair work
is done through the glove box opening and no disassembly of the dash or evacuation of the AC system is
required. Tools needed are a phillips screw driver, pliers, and a rotary Dremel tool or similar.  

The repair will take about half an hour to forty five minutes. No extensive mechanical skills are required.  This
JeepHeater kit retains dual temperature control and does not force you to sacrifice this expensive luxurious
feature.
$149.99
Dual Zone System repair kit
Single Zone System repair kit
$84.99
The JeepHeater single zone repair kit includes a solid
aluminum axle design which can be used for both single zone
Laredo and dual zone Limited style Grand Cherokee. Both
blend doors move together at all times.


Plastic housing not included. Your Jeep already has one.
The JeepHeater dual zone repair kit includes a two piece
aluminum axle design which can be used only for dual zone
Limited style Grand Cherokee. Both blend doors move
independantly from one another at all times.



Plastic housing not included. Your Jeep already has one.
$149.99
Dual Zone System
repair kit
Single Zone System
repair kit
$84.99
$149.99
Dual Zone System
repair kit
Single Zone System
repair kit
$84.99
Now stocking a wide variety of Jeep Tweeter Speakers, Door
Panel Retainers and Grand Cherokee Blend Door Heater repair kits
JeepTweeter.com is officially under new ownership as of January 1, 2011.
We will continue to bring great service and solutions for your 1999 - 2004 Jeep Grand Cherokee.