1998-2004 Jeep Grand Cherokee HeaterTreater - Heat and AC Blend Door Replacement Parts
NOTE: Knock-off products have begun to appear on EBAY and criticizing our products. Unfortunately this forces us to respond to incorrect statements from others. If you are considering a copy cat product at a lower price, please check the competition comments at the end of this listing. We have developed multiple blend door products for Ford, Dodge, Chrysler, and Mazda, and have more products in development. Inferior products attempting to copy our patent pending technology potentially cast doubt on our methodologies, and in an internet world that is deadly. We would prefer to take the high road and stand only on the quality and customer feedback for our products, but we are being forced to respond due to misleading and technically wrong statements.
WARNING: A supposed dual control blend door fix that is done through the glove box has shown up on Ebay. We evaluated a system using the existing rear motor axle to attach the back door. We rejected this scheme. Some details below and full engineering report on the tech section of our web site at www.heatertreater.net (to be added 7/14 when our webmaster is in).
Check
our other listing for the re-circ door fix also. Both fail modes are
common on the GC, and you need to check the operation of both systems to fully
understand problems. Combined purchase of both blend doors and re-circ
door at a discounted price can be made on a separate listing in my Ebay
store.
PRODUCTS AVAILABLE
1. HeaterTreater blend door fix
2. HeaterTreater re-circ door fix
3. Combination of above
4. HeaterTreater Pro (requires
Complete disassembly of dash)
5. HeaterTreater Pro + re-circ
This
is a kit to do a complete repair on the blend door malfunction that is common
to 98-2004 Jeep Grand Cherokees. It will work equally well on a RHD or
LHD GC. The most common symptom is a failure of the passenger compartment
heating system. This occurs because the broken blend door falls to the
bottom of the box and blocks the heater core. However, while loss of heat
is the most common symptom, the door can fall into different positions and even
shift or rattle around. In any event, AC can also be severely impacted
and at least compromised with a "gravity" seal against the heater
core in place of a blend door held in correct position by the actuator
motor. Every Grand Cherokee in this range either has, or will have, this
common failure. The pictures show a before and after shot of the
fix. All work is done through the glove compartment opening...no removal
of the dash panel or evacuating the AC system and draining the radiator.
Once completed, the alterations are behind the glove box and are not
visible. The work to install the fix is very simple, no more difficult
than changing your oil. Product returns are accepted within three weeks for a
full refund(minus shipping). The product changes the dual control Limited
GC to a single control from the driver's side temp control knob. A product to
maintain dual control is available in our store, but using the product involves
considerably more work to remove the entire dash, heaterbox, evacuate the
refrigerant system, and drain the radiator. The HeaterTreater(tm) solution
gives you the option of an easy fix with single control over both passenger
side and driver's side AC/heat, or a more involved repair process to maintain
separate control in the Limited GC. Cheap and easy...single control vs cheap
and hard...dual control. Your choice.
The Problem:
-
The Cherokee is built with Blend Doors to control the heater and AC
function. The controls are either dual control for separate
passenger/driver control or a single control system. The doors are
controlled by a stepper motor that seeks an open and close setting every 20
times the Jeep is started. During this calibration routine the motor is
overdriven creating excessive force on the components. The end points for
open or closed are set by a plastic pin that is part of the plastic door
assembly. When this pin breaks, the stop points become the open and
closed position of the door. Eventually, the doors will break(see
picture). The most common fail mode is for the broken door to fall to the
bottom of the box, blocking the heater core NO HEAT. Also, in this position, the door does
not do an efficient job of blocking the heat input, and the AC efficiency
suffers. The door can also hang in a position where it closes neither the
heater core nor allows full flow through AC evaporator. When this
happens, you have a constant mixture of heat and AC…too cold in the winter and
too hot in the summer.
- The Factory
solution is to replace the doors and housing with an upgraded part that has a
wider plastic pin to withstand the constant opening and closing when the
stepper seeks its beginning position. The repair entails removing the
dash panel, steering wheel, all vacuum and wiring harnesses, draining the
coolant, evacuating the AC system, and finally removing and repairing the
heater box. Quotes will range from $800 to $1400 for the repair...if you
can find someone willing to spend two days disassembling the car. It's
not difficult, just detailed, and evacuating and refilling the AC refrigerant
requires EPA certification. Dealers don't like to do this because it ties
up a technician for an extended period of time and the chances of missing a
wire or “Gomering” the re-assembly is high.
Do you have the problem?
The usual
symptoms are that the passenger side will loose heat, followed by the drivers
side. AC is marginally acceptable, but eventually no heat on either side
and poor AC performance since the broken door is not fully sealing the heater
core.
Grand Cherokee Single
Zone control(usually
- The blend door failure is not as
common on the
- You can physically check the operation of the blend doors by fully swinging out the glove box. There are two removable rubber stops at the top of the box opening and in early models, a dampener arm on the right side of the box(took them out in later models, and I'd suggest that you do the same).
- With the glove box open, you can see the blend motor to the left of the opening. The motor should move when you change the temperature setting. However, failure to move does not indicate a bad motor. The computer will shut the motor down if it detects a system fault. Either way, you need to remove the motor and check the axle before any diagnosis is possible.
- The motor is held in place with two Phillips screws. Disconnect the wire, remove the motor and you will see a plastic axle that is connected to the blend doors. The axle should have a limit pin on the white plastic axle(like the comma on a "Q") The GC failure occurs because this pin breaks, transferring the force of the motor directly to the blend doors. When this happens, it's just a matter of time before the doors break. Check for a broken limit pin on the axle and check that you can turn it ~50 degrees of movement between the two stop points.
- Start the GC and turn on the AC. You should be able to manually switch between heat and AC by turning the axle with your fingers.
- If the motor is spinning and not stopping, or the blend doors are not switching between AC and heat, your blend doors are broken and the HeaterTreatertm is the answer.
- If everything is working properly, the blend doors are not the problem. You might want to check my other listing on the re-circ door.
Grand Cherokee Dual Zone Control(usually Limited)
- The limited has automatic zone control and the driver and passenger sides have individual controls.
- You can read the fail codes on the system by following this procedure:
o Turn the ignition switch on and turn on the AC system. You should see a temp display for the two sides.
o Simultaneously hold down the AC and re-circ buttons while turning the drivers side temp control knob one click to the right.
o This puts the system into diagnostic mode and you should see a zero for no codes or if there are problems, one or more of the following codes. The higher number code is an historic fail code and the smaller number a current fail code.
15, 47 - Left temperature door not responding
16, 48 - Right temperature door not responding
21, 53 - Left temperature door travel too small
22, 54 - Left temperature door travel too large
23, 55 - Right temperature door travel too small
24, 56 - Right temperature door travel too large
20, 52 - Re-circ door travel too large (check our re-circ door listing)
54,56 are the most common fail codes and indicate a broken blend door. The system may still be marginally functional, but it will totally break soon.
o If any of the codes are present, the HeaterTreatertm is the solution.
o You can also
follow the diagnostic procedure listed above for the
The HeaterTreaterTM Solution:
This kit
replaces the plastic doors and axle with stainless steel components. All
work is done through the glove box opening and no disassembly of the dash or
evacuation of the AC system is required. Tools required are a phillips
screw driver, pair of pliers, and a Dremel tool(if you
don't already have one, this is a good excuse and the tool has many uses.
Target has a tool from DuraBuilt that is the cheapest I have seen and has
variable speed and a flexible extension attachment.). Dremel bit, hex
key, and all hardware is provided.
The repair will take about an hour, and once you have experience, you can do a
second GC in about half an hour. No extensive mechanical skills are
required. The kit is configured to change the dual control to a single
control from the driver's control panel. This is a necessary compromise
to insure the long term life of the fix. Both sides will have the same
temp setting with a single control. The passenger side knob still looks
like it works and you can adjust the temp display, it just doesn't do anything.
In the picture, you can see what your heater probably looks like. The
pictures are taken on an assembly that was removed from a Grand Cherokee.
The second picture shows the metal replacement kit. The third picture
shows the axle that is used to control the doors. It is ground to fit the
motor fitting. Note the steel roll pin going through the axle. This
is the new motion control stop, replacing the plastic stock solution.
The plastic doors are accessed by using the Dremel tool and bit to cut into the
plastic heater housing. Complete diagrams for the cutting pattern are
provided. It's a very simple process. The broken plastic doors are
removed and replaced with the HeaterTreaterTM.
The instructions are written with multiple pictures and dual level
instructions. You can read the bold print only for experienced mechanics
or read the bold and standard for full "instructions for
Dummies". The instructions are almost insultingly simplistic for
those who care to read the entire document without admitting that they did
it. The fix is really easy and MUCH preferable to disassembly the entire
dash and engine cooling systems.
100% Made
in
Customer Feedback
You can also check my feedback listings for additional customer
comments.
just want to say thanks for such a great invention! installed it
last nite and by dang it actually works!!!! you got something there i tell you!
good luck on more sales, you saved ME a fortune. i also posted a favorable
response to the ebay site.
I finally got a chance to install the heater treater and it
fixed the heat on the passenger side just as advertised. The heater box on my
2002 Jeep Grand Cherokee Limited was slightly different from the diagrams but
was fixed easily.
just installed the
heatertreater and much to my amazement....IT WORKS!!!!!!! easily installed and
HIGHLY recommended. the best thing is i keep thinking that i saved $1100!!!
still sucks that everyone has this problem, but mine is NO MORE! give it a
shot!
I just got my HeaterTreater and went to town with
it!! I read the directions for longer than it took to put in!!(45 minutes). I
am fairly handy, but never-the-less it was VERY easy to install. The worst part
is simply the scare factor of cutting into the plastic housings!! It went very,
very smooth - and my Heat and Air work again! As described, the dual climate
control no longer works, but the drivers control operates both sides. Not a
problem for me, since I usually turn both to the same setting anyway!! I would
definately recommend this to anyone who is tired of waiting for Chrysler to
even think about a recall - and/or those who refuse the $1500 -$2500 estimates
the dealers are giving
patent applied for.
Forum Posting:
The problem with the Grand is a design problem. The system uses a stepper motor that detects the extents of movement by hitting a resistance point at the open and close point. The system is designed with a small plastic pin on the door connection pin that breaks over time. When the pin breaks, the resistance point occurs when the door hits the extents of the open and close position. The door is not designed to handle this force and eventually the door itself actually breaks.
The factory solution was to re-design the door connector pin with a larger plastic stop. This will probably provide enough strength to last longer than the original design. The catch is that the housing also had to be re-designed to accommodate the larger pin.
If you just replace the blend doors without replacing the connector pin, the door will again break in short order. Trying to glue the door back together has the same result. You can try to use the upgraded connector pin with the old housing, but now the movement is restricted to an "almost open, almost closed" positioning. It works, but you get suboptimal heating and cooling. The only way to get proper operation with the Chrysler solution is to disassemble the entire dash, evacuate the AC system, and replace the entire heater housing. While the process is time consuming and exacting, the bigger problem is what you screw up re-assembling the dash and breaking the seal on the AC system. Dealers don't like to do the job because it generally results in follow-on work to fix what they screwed up.
The HeaterTreaterTM replaces the weak components with stainless steel replacements and provides the correct sized steel pin to control the extents of the door movement...will last forever. The work to replace the doors is all done from the front through the glove box opening, so no disassembly of the dash or evacuation of the AC system is required. I have spent a lot of time understanding and engineering a solution and this is the only viable solution.
Competition
NOTE: Knock-off products have begun to appear on EBAY and criticizing our products. Unfortunately this forces us to respond to incorrect statements from others.
- We use a thick wall stainless steel tubing for the door with a set screw to attach it to the aluminum axle. From experimentation, we can completely embed the set screw in the aluminum axle without stripping the stainless steel. Since the tubing is curved, the effective number of threads is greater than just a flat piece of sheet metal. The set screws will not loosen when they are tightened into a compliant aluminum axle.
- We originally tried to use a cut sheet of foam shelf lining for sealing the doors just like the competitor because it was cheap and easy. However, the air flow is into the end of the door and we couldn't reliably glue the foam to the door without having it loosen over time. The HeaterTreater uses a compliant PVC foam product certified for automotive applications and the foam wraps around the end of the door insuring 100% that it will not come loose from the constant air flow.
- Competitors state that the doors have 3/8" overlap of the opening, and 3/8" clearance to the edge of the slot that the doors move in. This is kind-of right for the door in the down position at the ends. However, when you move the doors up, the margin disappears. The sides of the door are the real concern and there you have 1/4" from the opening to the edge of the box. The door has to overlap the opening by 1/8" with 1/8" clearance. I would be concerned with products that were "engineered" by someone that has not mastered a ruler and uses incorrect numbers to verify quality compliance.
- Statements that the set screw will wear a groove in the aluminum axle and that there are not tight tolerances in the GC HVAC system show a fundamental lack of understanding of the most basic operation of the blend doors. On the GC, the doors have a limit pin that rotates between two stop points molded into the plastic housing. The force of the motor overdrive is constrained by the limit pins, NOT the doors themselves. The excessive force of the motor would be transferred to the HeaterTreater set screw attached doors only if the new hardened steel pin embedded in stainless steel tubing shears off.....ain't happening. Since the limit of door movement is from the limit pin and not the doors themselves, alignment of the pin and doors is critical to make sure that the doors completely seal against the top and bottom of it's range of movement. The system is designed with zero tolerance for any rotational variation. This is OK for a precision plastic OEM assembly, and would have worked except that plastic tends to break. For a metal door, zero variation is hard to achieve and particularly so with aluminum where it is virtually impossible to control warpage and alignment under high temperature welding processes. Precision aluminum assemblies are done with an expensive dip braze process for just this reason. In order to meet the zero tolerance requirement, we made the HeaterTreater adjustable. The door to limit pin alignment is adjusted by placing the door in the down position and tightening the set screws with the limit pin rotated against the stop point, insuring perfect alignment. This alignment is extremely difficult, if not impossible to achieve with a single piece unit. Yes, tightening the set screws takes an extra five minutes and it is a little frustrating, but it guarantees perfect alignment and operation. We have developed multiple blend door products and have more in development, and are committed to 100% perfect operation with no uncertainty.
- Personally, I would be doubtful of any "lifetime guarantee" offered on Ebay, but particularly from someone that purchased a well engineered HeaterTreater product 8 months after the launch and attempted to "design and engineer" a copy-cat product with no understanding of the operation and tolerances of the HVAC system. A lifetime guarantee on Sears Craftsman products means something and conveys certain legal rights to the purchaser. We stand behind all our products and will replace any hardware with no questions asked, but on advice of our lawyer do not advertise that as a lifetime guarantee.
- Dual control using the plastic rear motor axle is very problematic. The blend doors fail in stages. First the limit pin breaks, transferring the force of the motor to the blend doors. Now the plastic blend door connectors break. The doors are connected to a nylon axle that protrudes from the motor. This axle is stronger than the doors and the doors break, leaving the axle intact. In early evaluations, we duplicated the axle connector on a blend door and with a stronger door, tried to let the door absorb the force of stalling the motor. We found the third stage of failure...the plastic axle. When the door is strong enough to not break, the axle will shear off in 3-6 months. The axle is a 5/16" rod and the connection area is only 1/2" long. As we found when the axle broke, the axle is hollow beyond the connection area and very weak. As long as you have a limit pin, the axle is sufficient, but is not strong enough to withstand the calibration routine over time. If the back axle breaks, the back pin cannot be used as a pivot point for a single control product and the dash and heater box have to be removed to get to the back motor and replace the axle. I would make sure that the lifetime guarantee on the product covers labor and parts for damage caused by breaking the axle.
HeaterTreater is a reliable product designed by
degreed professional engineers with significant experience in control theory
and materials science. We don’t claim perfection, but have
over-engineered this and multiple other solutions to exceed functional
requirements. The HeaterTreater is the original and best product and we
will bend over backwards to make sure that the system works in your GC, and
fully stand behind our products.
HeaterTreater
