I have a 2003 dodge durango and the rear heater is blowing just cold air while the front heater works fine. Is there a rear flapper that is stuck and where would it be or is this a clogged heater line. Let me know if anyone has had this issue. Thanks

 

Garo

Both scenarios are possible. Get down behind your passenger side rear wheel with the heater fired up and engine warm. Feel both hoses under there. If both are hot, you most likely have the flapper issue. If not, sounds like a clogged core, or possibly low coolant level.


Don

 

The flapper is located inside of the rear interior panel that corresponds to the hoses entering the truck from underneath. The blower unit, a/c condenser, heater core, temperature selector flap/actuator and vent/floor selector flap/actuator are all behind that panel connected to one large unit.

It takes a bit a disassembly of interior panels to get in there to do the work, but it's nothing terribly tricky if you're used to working on car interiors and are handy about it. Just be warned, there are a ton of screws if you have to go in there.

Definitely check the core for hot send and return hoses first. It could save you a lot of time and hassle. If those are hot, then you'll have to check out the actuator door. I kind of had to carefully pry the unit apart to inspect it, remove the broken flapper/pieces, and install the replacement.

I got a replacement actuator and flapper door for about 20 bucks at the junk yard and it took a few hours to get in there and finagle it into place and reassemble everything. I tried to avoid taking the whole thing out and succeeded.

If the actuator flapper door failed, I'd have to suspect that either the collar that connects it to the servo motor broke and/or the door's mount broke. The servo motors don't seem to fail. Unfortunately, the actuator servo that drives the flapper door is very powerful and can easily overpower the little plastic tab-stops on the assembly. Once those fail, the door travels a bit further than it should, and then bottoms/tops out inside of the HVAC unit. At that point, the actuator keeps going and then snaps off the flapper's mount.

Once it is broken, the flapper door just lays on top of the heater core, which allows the air to just bypass the heater core altogether, much in the same way it would had it been fully functional and you selected cool air (or AC).

Since the part and servo I got from the junk yard wasn't broken, I figured it would be worth using the servo motor that came with it instead of keeping the one that broke the other door in the first place. It was a slightly different make than the one I had in my truck, but it was still a plug & play operation.

I really wouldn't let the dealership do this repair, as it is a little on the labor-intense side for disassembly and reassembly. The part is cheap and the actual repair is quick though. On top of that, the dealership will want you to buy an entire new side to the HVAC unit, which is big $$$ and much more than you need to buy. Who wants to buy the entire unit when all they need is one or two small parts? It saved me a ton of money to do it myself (as the rear heat and a/c is really not a crucial system anyway), and it shuts up winy passengers in the winter.

Good Luck.

 

Thanks. Do these heater lines run under the car or under the lining inside the roof of the car

 

They run under the truck and enter the underneath side of the rear passenger side corner. If I remember correctly, I think there are 2 hoses (heater) and 2 hard lines (air conditioning) under there.

 

I have an 01 Durango SLT, 4.7L and my Rear Defroster button is Flashing and the AC button next to it is inoperative as well. Also cold air blows out in the rear(Front heat works fine). Took it to the dealer where they scanned the HVAC module with a DRBIII scanner and a "Rear Blend Doors Broken" code popped up.

Took the car back and I disasembled the passenger side interior trim myself exposing the whole Heater/AC Assembly. I found that the first door flap and white plastic *** that controls the door flap which circulates between hot air and cold air is broken. Acuaters seem to work fine.

Question is:

1) Can this broken door flap Actually affect the electrical system causing the defroster light to Flash endlessly???

2) Do they sell the door flap assemly and white *** seperately?

3) Can the repair be done by removing only the outter half of the Heater Assembly? OR does the WHOLE entire Heater unit need to come out?

4) Lastly, after the repair is complete does the HVAC Module have to be reprogrammed with a DRBIII or will the repair take care of the Flashing Defroster Light and door flap positions by itself?

Thanks guys! -Chris

 

the blinking defrost light is either a bad control unit, or an open circuit in the defroster for the rear window or the side mirrors (they are on the same circuit)

the A/C control not working kind of makes my gut scream that the hvac control unit is going bad, unless the clutch is unplugged (or not getting power), however i would expect a light of some sort if this were the case

im not sure on disassembling the door flaps, however they should NOT cause issues with the electrical systems that is probably another issue

 

I also have a 2001 Durango, and have been working the same problem with my HVAC system. I found the limit tab on the white **** that controls the temperature control door broken off. When I turned the **** by hand there was no resistance, and I could spin it endlessly.

I really didn't want to break into my water and refrigerant lines, as the manual says to do, and then remove the entire HVAC housing. So I managed to split the assembly in place. You basically have to remove all of the screws that join the halves. There are three screws that hold the fan unit on the housing, I removed the two that were accessible--the one in the back I reached with a long screwdriver and simply loosened it but left it in place. This allowed me to get the housing split apart enough to see what was going on.

Indeed, the flapper door was laying in the bottom of the housing. The hub of the door axle was split where it slips over the splines of the white actuator ****. Those actuator motors must make plenty of torque. An inspection mirror showed that the white **** splines were intact on the inside of the housing.

So at this point, I'm not sure what I will do. I will check on new parts availability, and may attempt to simply repair the parts myself.

I read on a different forum some time ago that someone had a somewhat similar problem, but in their case, they managed to glue the limit tab back on to the **** and everything worked after that. If we could be so lucky...

One question: If I repair/fix this, does anyone know if the rear heater unit will require recalibration with a DRB? My hope is that it will just sense out the limits and self calibrate.

About the blinking defroster light noted above. Several years ago I had a problem with my front HVAC (repaired under warranty) and when we picked up the vehicle, (after repairs) this light was blinking. The dealer service rep explained that the blinking light is simply a notification signal, and that the system would function normally. Apparently the system still needed reprogrammed, and their technician that specializes in this was not available. I took the Durango back in a few days later and the light wasn't blinking after that.

 

Does anyone have pictures of the location and the flipper?

 

Here's what I found out and what I did to fix my rear HVAC. It turns out that Dodge no longer offers a replacement temperature blend door, at least by itself. It seems they realized a design problem, and so they have redesigned the half of the HVAC housing that holds the actuators and doors. So to get a new flapper/door, you've got to buy the whole half of the housing. Which also means you probably have to remove the whole unit from the vehicle to do this work, too (mine was still in the rig). Cost? $189.00. So I decided to attempt to repair the broken piece myself.

The good news is that the actuator ****, actually called a coupler, is available, and so for $10.10 I had a new coupler. This saved me the trouble of trying to repair the broken limit tab from the original coupler. The parts look like this:



The flapper door and it's broken piece are obvious. The new coupler is the black piece. The broken limit tab from the original coupler is the small white piece. Note how they've redesigned the coupler tab as a beefier lug that runs the length of the coupler hub.

I epoxied the door pieces back together, and reinforced the joint with some small gauge wire. Everything went back together fairly easily. Here's the HVAC housing before replacing pieces:



The white "****" in the middle near the heater core plumbing is the original actuator coupler. I drilled this out and replaced it with the new, black coupler.

After getting it all back together I ran it through the different operating ranges. Thankfully everything worked. The system appears to self-calibrate. The temperature actuator cycled itself from one extreme to the other, and then the unit responded properly to changes of the temperature setting. One problem -- I noticed that when the coupler was rotated to full clockwise, it appeared that a fine crack was just starting to open between the HVAC housing and the limit stop built in to the housing. So I made an aluminum support for this limit stop, not wanting to have to tear into this if the limit stop broke later.



Hope this is useful to you guys/gals.

(And I hope the pictures show up correctly)