I own a 2004 Chrysler Pacifica, and the front fan stopped working. I replaced the front blower motor resistor with three (3) new ones. I know the man at the local AutoZone who took them back. Replacing this unit with a new one did not fixed the problem.

What I discovered if I run a wire between the negatives of the blower motor resistor (black to black/orange wires) the fan stay on high speed and nothing on the control unit (changing the fan speeds or turning the unit on/off) changes the fan speed from being on high.

Do you know what the issue is with my car? I am clueless at this point.

 

get a test light and check for the power and grounds at the resistor and the motor itself

 

I will test power and grounds at the front blower motor resistor and fan motor and this weekend? By testing this, what am I trying to narrow down to be my problem – i.e. a bad fan motor or something else?

 

power will be there all the time ground will come from the ac control head through the resistor unless u have the auto temp control them its pulse with modulated and u cant test it.

 

I appreciate you taking your time in helping me resolve my problem. My car has an automatic climate control with dual tempature.
Not sure what my next step should be.

 

Hi.
If you have the auto-climate control, fan speed is not controlled with a simple resistor pack.

It is a pulse-width modulated 'Blower Control Module' like this:

CARAVAN TOWN COUNTRY BLOWER MOTOR RESISTOR MODULE MOPAR | eBay

The typical failure mode is that the fan runs uncontrollably at high speed regardless of the the manual setting - you'll see the 'speed bars' on the display change, but the fan will run full speed.

Remove/replace procedure is the same as the resistor pack.

 

And...the failure is usually the MOSFET power transistor in the module. If you are handy with a soldering iron and so inclined, look up online or visit your local electronics supply house and buy a Fairchild N-channel MOSFET part number HUF75343P3.

The MOSFET will cost you ~$2.00-$3.00
The entire module is $50-$100.

I have repaired several with good results and no further issues.

 

Goldsmi -

I purchase and tried three (3) new blower motor resistors, and "the typical failure mode of the fan running uncontrollably at high speed regardless of the the manual setting - l do see the 'speed bars' on the display change, but the fan will run full speed." Still happens.

The only twist to make the typical failure happen is that I need to run a wire between the negatives of the blower motor resistor (black to black/orange wires). If I do not run the wire, the fan does not blow at all.

 

Please clarify - You stated previously that you had auto climate control - You need the 'Blower Control Module'. You should not be trying to use the resistor pack.

 

The part I replaced three times is the a/c Heater blower control switch. Below is the link.

Duralast/A/C Heater Blower Control Switch (JA1623) | 2004 Chrysler Pacifica AWD 6 Cylinders 4 3.5L SFI SOHC | AutoZone.com_

I do have automatic climate control with dual control.

The only way for me to make my fan run on high and have the typical failure you described is to run a seperate wire between the negative (black to black & orange) of this switch.

Not sure why the grounds are not connect between the two plug in on this unit.