quantrill88

As I know is common with these trucks my blend door went out. Searched out the Heater Treater replacement, purchased, installed the actuator (quite a pain as promised lol), yet I'm still getting defrost only.

Has anyone else had this not correct the blend door, and if so has it been a problem with the re-install (re-indexing the gears, something getting jarred out place while trying to install the back screw?), or something further that needs replaced. Have also disconnected the negative terminals as directed.

For anyone that's done one, accessing the blend door motor and actuator is not fun given its location. Hence hoping to see if anyone has any input before I pull it out again.

Truck actually has its original uncracked dash so I was really hoping the Heater Treater actuator would solve the problem.

Thanks in advance for any insight!
- Jeff

johnh

i never heard of that problem with the 01, '02 and up are different

quantrill88

https://www.dieseltruckresource.com/...-motor-310637/

Other than the plug one member mentioned there's not many other problems with the Heater Treater fix. Going to pull it out again on my days off to check but am wondering what's the next step if more than just the blend door motor is bad.

- Jeff

Danderson

I always set my fan to low before using the HVAC system to minimize strain on the under engineered doors.

Busboy

The blend door only blends cold air with hot air and on a 2001 is electrically operated, ALL the other doors are vacuum operated so you have a vacuum problem. As defrost is "default" mode you probably have no vacuum getting to the rotary vacuum switch. I would look for a vacuum hose off first by the fuel filter up high on the fire wall, if that's ok then the vacuum line passes through the firewall where the AC lines go through, it's a small black plastic line and can become brittle over time.

quantrill88

Thanks Busboy, I appreciate that and you explained it perfectly!

I jumped on the blend door being the issue as the truck was showing the tell tale signs of the a/c kicking off and defrost only.

That being said vacuum is where this all began. Somehow the line that runs across the firewall from the passenger to drivers side got a hole in it. Found line and fixed it returning a/c, cruise, and 4x4 functions. Immediately after this I had defrost only. Looked and looked for another broken vac line but perhaps I didn't look hard enough.

Heater Treater seemed worth a try, the actuator was broken upon removal, which may have reinforced in my mind that this was the problem.

Only one day off this week and am headed out to take a look again at it now. Fwiw still gonna remove and check the blend door motor but will spend some more time under the hood.

Thanks again,
Jeff

quantrill88

FWIW, removed the blend door actuator motor yesterday. Double checked everything and triple checked the indexing of the gears. Reassembled, pulled negative cables as suggested in directions. Can now hear the motor turning and have defrost (of course), floor, and a very weak airflow from the dash vents.

Also inspected all vacuum lines I could find but found none broken.

While the hvac was starting to have progressive issues, the "defrost only" mode began after the Vac line that runs across the firewall broke. As stated earlier I fixed the line and cruise and 4x4 returned hvac stuck on defrost.

Not sure what to think. Motivation is getting lower as the temps start dropping (not my DD anyways) but feel like I'm either missing a vac line somewhere or something is up with the blend motor. The Heater Treater did seem to perform as advertised as I can tell the motor is moving again but perhaps that was only part of problem.

Will certainly update if/when I find the culprit.


- Jeff

Busboy

You can buy a small hand held/operated vacuum pump with a gauge for around $30 (also good for bleeding brakes). Hook this up to the vacuum line going through the firewall and draw down a vacuum, let it sit and see if it deceases if not then the system inside the cab is good, next operate the controls out of DEF mode with the fan on and see if the air moves. If it does then you have a vacuum leak outside the cab. If the system inside the cab is leaking it will probably be a vacuum actuator but could be the rotary vacuum switch. Dodge says the switches are not individually replaceable but that is not true. The switches can be individually replaced, you just can't buy them from Dodge so a wrecker.

Just reread your post and you say def AND floor is working OK? with slight air flow from vents. If this is true it's either the vent actuator or the rotary switch, but check line going to actuator first.

quantrill88

Thank you very much! Been working a lot lately w/o much time to work on much less drive the truck. Got a day off though and will put this on the list. Temps are finally getting nice here and with limited space to work on the truck Goya squeeze lots in this fall.

Once again, thanks for the response. Will check back with results.

All the best,
Jeff

BarryG

I am with Busboy on this one. On my 01 I had to do the heater treater fix for the door. The little thing it sits in was cracked and the shaft just spun in it. It only affects the temp of the air not where it comes from or should say goes to. As he said there must be vacuum issue somewhere. It could even be inside the cab or maybe it is pinched off/kinked outside in the engine compartment. IIRC there is only a couple t's under the hood for it. I also seem to recall that one of my t's had an unused port that was open or appeared open as there was nothing hooked to it could you have possibly hooked the vac line to the wrong port on the t. I have no idea what happens if you do that just thinking out loud, well on the screen anyway.