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Thaeric 11-30-2011 10:26 AM

No Heat - and winters coming!
2002 Dodge Ram Quad Cab 1500 4.7 sport 4x4
Last 8 of the vin: 2J238687
(Single zone climate control)

Summary of Problem:
No heat from any vents (floor, defrost, or dash).

What I've checked/done so far:
Blower motor checked - Ok
Heater core is working fine - have checked both hoses and they're both hot to the touch and roughly the same temperature.
Coolant level has been checked - Ok
Have let the truck run with the radiator cap off hoping any air in the system would be flushed - no change

Description of issues:
A month back the heat was great, would literally burn you out if you left it on high for too long. About 2-3 weeks ago, that suddenly, and without any warning signs, stopped. At the onset of the problem I noticed while playing with the controls that there was some heat coming out of the vents on the passenger side, but only cold air on the driver side. More testing of the controls, (and listening for blender door movement and vacuum leaks) over the following days resulted in absolutely no heat even from passenger side except when the fan is set to absolute lowest setting - and then only a very faint amount of warmth can be felt from the passenger vents. Shutting the fan off for 5-10 minutes and then turning it on low results in a short burst of warmth from the passenger side, but it quickly returns to cold.
When changing climate control settings I can hear the changes occurring - not sure if I am hearing an actuator or maybe the doors moving, but something is definitely moving with all adjustments, leading me to believe that the controls themselves are working.

I've done quite a bit of reading on this, and it seems that a fair number of people have had problems with blender door failure which results in the same symptoms. I'm leaning towards that being the issue - but I am disabled and not exactly wealthy so I need to try to make sure whatever I force myself to do (or pay for) is the correct problem as I may only get one shot at it before spending the winter shivering.
Can anyone think of anything else to check/try? Any other symptoms I should check for to validate that this is a blender door issue before pulling stuff apart to try to get to it?
From what I've listed here, does this sound like a blender door problem to you?
If I end up having to pay a shop for this repair, any estimates on what kind of price range we're talking about?
If I do try to tackle this myself, are there any resources (images, guides, etc) that you guys care to share or point me in the direction of?
I've read that it's not possible to repair this (if it is the blender door) without pulling the dash - something I am dreading because I'm not sure I can physically do that anymore, is that true? or is there a way to get to the problem without ripping out the dash? Where exactly would the problem be located at?

If there are any other details that I left out, or if you have any specific questions about the issue or the truck please let me know. I'm more than willing to answer anything I can and if necessary perform any tests I am capable of doing to work towards fixing this.

Thanks in advance everyone.

HemiLonestar 12-01-2011 10:53 PM

If you aren't getting any air from your floor, defrost or the vents, then where is it coming out? It does sound like blend door failure, but if your fan isn't busted it has to be blowing out somewhere.

kewlguy53403 12-01-2011 10:58 PM

I had this issue in a previous vehicle. Turns out I had a leak in my coolant and air was getting in the line. Check your coolant. My leak was so small it didn't leave anything on the ground, putting me in a similar position to you pulling my hair out.

Thaeric 12-02-2011 11:18 AM

@ HemiLonestar: As I said in the original post, there is airflow coming from the vents, just not heated.

@kewlguy53403: As I indicated in my list of things I've already done, I've checked the coolant level and verified that it was where it was supposed to be. Additionally, the heater core and hoses are heating up properly. A leak is not the issue.

bigdaddyII 12-04-2011 07:54 PM

It may be the door that opens up the heater core and blocks off the evaporator core. Is the air only cool or is there no change in temp when you move the setting?

Thaeric 12-05-2011 12:19 AM

I had a friend come and help take a look under the dash today. He pulled all of the lower panels and the center dash piece. Here is what we found...

The recirculation/fresh door was verified to be working correctly.
Both mode doors were verified to be working correctly.

However we could not verify that the 2 blender doors were working correctly. Both of the molded stops on the outside of the plenum box were intact and seemingly good condition.
We removed the motor and verified that it was working; and that the teeth both on the motor and the receiver were in good shape.

We could not get the bar between the two blend doors to separate and thus we couldn't test them individually.
However, when the bar was lifted upwards we could hear and feel a difference in the airflow, and there was some heat coming from the passenger side vents but not the driver side, defrost vents, or floor.

When the bar was moved downward, all heat stopped and all vents went cold.

Is there a special way to remove that bar from the two arms? We spent about an hour trying to find a way to remove it without breaking anything with no luck.

Also, I found this...
"The symptoms of blend door failure are an inability to control the temperature of the air flowing through the system. A broken door will generally fall into the down position, blocking the core and having no heat in the system. The box is designed for either single or dual control of temperature on the passenger and driver’s sides. If there is a difference between passenger and driver’s side temperatures, the problem is with the blend door on either a single or dual control system."

Found here..

Can anyone verify that this is accurate? Has anyone ever used any of heatertreaters products? Have they worked for you?

GTyankee 12-05-2011 01:27 AM

although i have not yet had this issue, i recommend the Heater Treater website as a reference

On YouTube there are several videos covering this very subject on Dodge heating issues, you will see the videos at the end of each video, at the bottom of the screen

Bronzebird 12-05-2011 03:59 AM

I guess you coolant level never dropped to "ADD"?

Originally Posted by kewlguy53403 (Post 665401)
I had this issue in a previous vehicle. Turns out I had a leak in my coolant and air was getting in the line. Check your coolant. My leak was so small it didn't leave anything on the ground, putting me in a similar position to you pulling my hair out.

I had to add coolant and now have luke cold air not warm at all. I'm trying to find the leak and thinking heater core with faint smell of coolant in the cab...

starquestbd22 12-05-2011 08:12 AM

Just probably figured this out when you looked at it carefully but there will not be any vacuum leaks because all of the Ram HVAC doors are electronically controlled with a tiny motor. That's actually the reason the doors are so prone to fail. The motors overdrive the plastic doors and stop pins and they eventually break.

I have not used any of Heatertreaters products (because the only door I have had fail thus far is the recirc door and I just blocked it off) but they seem extremely comprehensive and knowledgable. Their kits replace the stock plastic doors with steel doors that obviously aren't going to break. They also have detailed instructions that can guide you to replace every single door except for one...I think it's one of the mode doors, the one that controls airflow from defrost to floor....without pulling the dash. I have also read a lot of reviews on them and most folks say the instructions are very simplistic and easy to follow. In short, if I develop a need I won't hesitate to purchase one of their products.

Lastly, I do not know how to remove the bar that you are talking about....the one that connects the two blend doors I think? I do remember seeing them do it in one of their diagnosis vids on youtube and it seems simple. That information you linked from them is accurate though. If the blend doors fail and fall in the down position they will effectively cut off the heater core. The core is sandwiched between the two doors in a horizontal position and there is a door on each side of it. With the doors closed it's completely blocked off. Hope some of this helps. Good luck and keep us updated!

Thaeric 12-05-2011 09:06 AM

@ Starquestbd22,
Yeah I realized after we pulled the dash apart that we weren't dealing with a vacuum system. For whatever reason I can't edit the OP though, so that is stuck in there.

I've done more reading on it all and it definitely sounds like the blender door failed. I just can't figure out how it failed while the limit pins are still intact. Just doesn't make any sense.

I've watched the video where he's messing with the blend door, and he does remove the metal bar, but does it between cuts of the camera so you don't get to see how he did it. It does however show him putting it back together, and it's simply a notch cut in the end of the bar to give it a groove to snap into place.
I guess it's just a matter of getting enough pressure on it to pop it out.

My friend suggested putting a small hole in the side of the box where the door is to be able to see if the door is moving. If it is getting stuck in the down position we may be able to lift and prop it up with a small rod or something for the time being until I can get a hold of the heatertreater kit and give that a shot. Some heat at this point is better than none.

Thank you to GTyankee and Starquestbd22. I'll let you guys know what happens.

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