My 2004 Pacifica HVAC system has stopped functioning properly. The fan runs at top speed, no matter what temperature is requested. In the auto or manual, all I can change is the temperature and output port. I can not change the fan speed regardless of the temperature requested or trying to change the fan speed.

I noticed that when I try to turn off the system, the fan appears to run even faster! Bottom line, I can't slow it down and I can't stop it!

Any ideas what has failed? I kind of expect repairs not to be cheap, but does anyone know the ballpark for repairs?

Many thanks....

---Paul

 

Hi,

Based on experience with other cars - have not dealt with the issue on a Pacifica - you are describing a failed HVAC fan resistor. The fan is really designed for its highest output, and then the resistor reduces input power to create the lower speed. Older cars had a 3 or 4 level resistor and the newer vehicles with automatic systems have a variable setup to allow any number of speeds.

Rockauto shows one for $60.99. I could not pull an OEM price online but I would guess $75 and up. I'll take a look in the manual and see where it is located. Older setups were almost always behind the glove box but I did change a variable resistor out on an Explorer and it was on the firewall in the engine compartment.

 

Hey, take a look here. Looks like the OEM descriptions call it the "module" when looking under the HVAC fan listings. From their illustration it looks to be under the glove box near the fan - I am assuming from the illustration that the fan shroud they show is inside the car - again have not yet "been there" on my Pacifica.

 

The problem is, no doubt, the Blower Control Module.

The Automatic Temperature Control system uses a 'Blower Control Module', not the usual Resistor pack.
It is located behind the Glove Box. Drop the Glove box down, disconnect two electrical connectors, remove two screws to get the module out.

Simple 10 minute job.

As stated, Get the part from RockAuto or eBay for around $75.

 

My problem was that the fan would not work at all. I read this a also cause by the Blower Control Module and replaced it this morning and everything is working again. The part has been upgrade and has a new part #, 5179985AA. Cost me $60 plus shipping. Here are a couple of pictures. Looking at where it is, behind glove compartment and the part it itself. This picture is the old one, the heatsink is different on the new one.
Remove the two screws and pull the module out. Unplug the two sets of wires and you will see this part (this is a Pacifica with AUTO TEMP. CONTROL), the part for those without it, looks much different. Probably disconnect the battery to be safe.

Jeff

 

Hey guys, this just happened to me on the weekend as well, was about to take it to the shop when i thought about checking here first. how would one find out if my 2004 pacifica had (Auto Temp Control) or not, as when ordering the part, there are two. Thanks, Fred.

 

If you set the temp for your heat, does the fan speed automaticaly adjust as the inside of your car gets warmer? If yes then you have "automatic temp contol". If you have to adjust the fan speed, then you don't.

 

If you have a big **** that you turn for temp and has red and blue on it you have manual.

 

I have this problem in a 2000 300M.
I replaced the module and it worked normally.
Two days later back to the same problem. Contacted Rock Auto. They supplied another module which did the same thing.
What else can be causing this problem?

 

The power module repeat failure is typically caused by the fan motor drawing excessive power. Dragging bearings or just dust from age causes extra load to spin the motor. I have also seen the blower wheel slip down the shaft rubbing on the housing. This causes excessive amp draw that cooks the module. You might be able to free up the motor with some light oil.