https://dodgeforum.com/forum/3rd-gen...0-minutes.html

^^^
Armed with information from this thread, I set about the task of trying to rectify the paltry airflow coming from the vents in my 03' quad cab. With fan turned to full blast, you can hear the fan loudly doing it's job, but the airflow does not match its vigor.

I was sure I would find the famous "recirculation door", broken and blocking air flow, but alas, this was not the case. When I removed the fan and looked up into the hole. The door was fine and in a closed position.

Here it is, looking up into the hole after fan removal.




The door drops open when I set the mode to defrost and closes when I turn it off, so I wouldn't even call it a recirculation door. More like the defrost door.

Also, another oddity. I removed the glovebox thinking I could easily get to the vent door behind it (I was so sure it was the door, I removed it first LOL). The way the manual describes glove box removal didn't work for me. I simply removed the six screws at the bottom hinge. Anyway, that revealed a solid panel and to take it off, I'd have to take off the entire dash surround which overlaps it on the left side.



Anyway, back to the problem at hand. This whole vent system frustrates me and I don't know much about it. The current air flow is adequate...the AC cools nicely and the heat is like an inferno, but I'd still like to get full flow. Anyone have any other ideas about what's blocking it before I button this all back up? Should I just give up and leave well enough alone?

 

I had this same exact problem with my truck and living in Florida you need cold AC and good air flow. The air flow from my OEM blower fan was pretty weak. On the highest fan speed it still did not move much air at all. The air flow from the dash vents was pretty bad and from the floor vents it was worse, nearly non-existent. Like you, my recirculation door was working fine, I could see it move when I changed the setting.

I replaced both the blower motor resistor pack and the blower motor itself and it is like brand new again. The air flow from the dash will blow my hair back on the highest speed. I also get decent air flow from the heater vents. It's not as strong as the dash vents but it is still a lot better than it was before I replaced the resistor and blower. I bought the Factory Air brand of blower and resistor from Advance, used online discount codes, paid online but picked the parts up at the store myself and saved about $50.00.

I replaced the parts maybe 3 years ago, probably had about 130,000 miles on my truck at the time and the system is still working fine and provides a lot better air flow. When I replaced the resistor and blower I first tried just the resistor pack by itself. It helped somewhat but the new blower fan really fixed the problem. One thing I have noticed is the colder my AC gets the more velocity I get from the air flow out of the vents. Colder air must be easier to move I guess. It was easy to do, both the resistor pack and blower come out from under the bottom side of the dash below the glove box.

Jimmy

 

You may very well be right, but how was your fan sounding before you changed it? Mind sounds really strong and loud at full blast, like it's the air being throttled somewhere.

 

My OE fan was not that loud, pretty quiet I guess but it also was not moving much air either. The fan I got from Advance is louder on the highest speed than the OE fan but it moves a lot more air. It has gotten quieter or maybe I just got used to it over the last few years. The new fan is a definite improvement. Maybe try disconnecting the wiring connector and jumping fused 12 volts and a ground from the battery to your fan and see if it improves the air flow. If it does you may just need a new resistor pack. I remember testing my OE fan and finding it was drawing too much current. If I remember it right it was drawing about 19 amps, which I read that 16 or 17 amps on high speed is about the limit for a good fan. You could have an obstruction somewhere in your vents too but who knows how to test for that?

Jimmy

 

Thanks for the advice. I'll try measuring the current and direct wiring to the battery as you said. Also have bunch of Dakota's near me at a u-pull-it. Might pull a resistor and fan off one.

Regarding the resistor... is this is what's stepped to change current flow for each point on the fan control ****? If so, the highest level being of least resistance? I'm wondering if bypassing it might damage the fan, but you did say fused. Guess I can be quick about testing it.

All in all, my hunch is that there is another door broken somewhere but I'm not pulling the dash out to get in deep...well, maybe if I knew which one for sure.

 

Yes. the blower resistor is really 3 or 4 single high power resistors in one casing which gets stupid hot and will melt anything plastic, rubber, or electrical near it. Usually what happens is that the terminals melt apart causing increased resistance. You can bypass it with a fused wire, but it will be stuck on high speed.

actually, redact. Is the resistor on the power or ground side of the fan? I could have sworn ground side, but maybe that's GM and dodge is power side?

 

There is a blend door inside the HVAC box, and it is controlled by an electric actuator. Maybe the door is obstructed or the actuator is bad. I think the Dodge dealer guys can use the DRB scanner to communicate with the actuators and recalibrate the doors, if you don't find anything with your testing maybe the Dodge guys could check it for you.

The resistor does change the ground going to the fan, high speed does have the least resistance. At the fan the green wire has 12 volts when the ignition is on, the black wire is ground. It will not hurt anything to disconnect the fan plug and jump power and ground to it. The blower resistor going bad is a pretty common problem on Dakota's. I changed mine twice before checking and replacing the fan motor itself. You even read on here about resistor packs that got so hot it melted the wiring connector at the resistor. That is definitely from a fan drawing too much current. Advance sells the resistor pack pretty cheap, $12.00 and it works just as well as the OE part but it costs less. Dodge sells the resistor for about $20.00 here. I myself would not use any electrical part from the junk yard, you have no idea how reliable or un-reliable it might be.

Jimmy