QuestionQUESTION: I am having a few issues with my 2002 Chrysler Voyager. The fan ONLY operates on "HIGH" which I figure has to do with the resistors within the control unit... Can I replace the resistor pack without having to buy a whole new control unit? Also, my blend door has not been operating properly, I have a fully functioning A/C compressor with the perfect amount of refrigerant/lubricant in the system, but it goes into a sort of "neutral" temp when I turn the knob all the way to "Cold". HOWEVER, If turn the knob two clicks away from "Cold" and towards the "Warm" side it blows freezing cold air... Could this be due to a rheostat/resistor problem within the blend door SWITCH in the control unit? Or the actuator itself attached to the blend door? Thank you for your help
ANSWER: Hi Frank,
Fortunately I have the '02 shop manual for the minivan. I assume this is the manual temperature type of unit rather than an automatic temp unit where you request a given temperature. In either case, however, the blower speed control is not inside the control unit but rather is mounted in the HVAC unit under the dash. It is called a resistor block for the manual unit and power module in the case of the ATC type of unit. You gain access to it by opening the glove box, then gently squeeze on the sides of the box near the top edge so that the rubber stop bumpers clear the sides of the opening and then roll the box downward and out of the opening. You will then see a small rectangular item held in the HVAC unit by a couple of screws and which has 2 plugs going into it. Remove the plugs and then the screws and the resistot block/power module will come out for replacement. Install is the reverse. The run only on high speed is typical of a block that has a burned out resistor or more and replacing it will solve that issue (similar with the power module if you have the ATC type)>
On the blend door, I would begin by asking the unit to do a self-calibration of all its door actuators. With the ignition switch in the run position, press and hold for at least 5 seconds both the power and recirculation buttons (on the manual type of unit). Then release the buttons and the power and recirc LED's will commence flashing and do so for about 2-3 minutes. When the flashing stops the calibration is done. If the flashing continues beyond three minutes it means that there is a fault of some sort which can be determined by a plug-in diagnostic readout box capable of communicating with the HVAC control unit. The light will stop flashing after you have driven the van 8 miles or so in any case.
But even without that plug-in fault code readout, if the issue is the blend door, then you could try replacing its actuator after first removing it and trying to move the door connector by hand to be sure the door isn' jammed. But the self-calibration may correct your problem so try that first. I'll tell you about the actuator if you need to try that.
Please "rate" my answer (see below).
Thanks,
Roland
Roland
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QUESTION: I have just removed the resistor block, should I be looking for anything that tells me there is a resistor blown, or should I just replace the resistor block anyway?
I completed the recalibration as you told me to do and the recirculation button continues to flash beyond 3 minutes, however as soon as I start the car the blinking stops. I'm assuming this means I have a have an HVAC fault. How can I access the blend door actuator? Thanks again for your help
ANSWER: Hi Frank
Accoring to the manual the flashing is supposed to continue even if you turn off the key when there is a faultn andit lasts for 8 miles of driving. So try the system out now to see if the calibration might have corrected that problem. If not then here is how to get to and observe the blend air door:
The temp controlers for the front HVAC are on the left end of the HVAC unit. You have to remove the underdash panel to the left of the steering column to see it. That is done by removing the screws from the parking brake release handle and all the screw around the edge of the panel, then disconnect the parking brake cable from the handle and finally remove the handle. If you have ABS the ABS control module will block your view and so that has to be removed. Once you can see the left hand end you will see 2 or 3 actuators for doors inside the unit (3 if you have a separate temp control for the passenger, otherwise 2). The upper actuator is the distribution of air device, while the lower 1 or 2 moves the air temp door. You could try changing the requested temp and watch/touch/listen to see if the actuator appears to respond.
On the resistor block, it should have 6 pins arranged 123
456 or it might be the left=right mirror image. In any case, if you the block is good you should see maximum resistance between 1 and 6 and then decreasing resistances as you measure from 1 to 5,3,2 if all the resistors are good. You can probably visually inspect them and verify their condition. Blowing on high only means no resistor in the line from the motor to ground so it runs full tilt, and full tilt only. I am virtually certain the block has a blown resistor or more.
Thanks for the rating and nomination. You may do it again if you would like to.
Roland
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QUESTION: Thank you so much for your assistance Roland. I replaced the resistor block with no further issues related to the blower speeds. I have removed the lower dash panel under the steering wheel column and I found the actuators you mentioned. The one on top that distributes the air works just fine. The lower actuator (while still mounted) seems to turn fully clockwise when I turn the knob to the "HOT" position... HOWEVER, when I turn the knob to "MAX COLD" position, the door makes a sort of "thump" sound and the actuator seems to "click" as if something was obstructing it as it approaches "MAX COLD"... I tried turning the temp knob towards the "MAX COLD" in increments of one "click" on the temp knob, starting all the way from the "NEUTRAL/WARM" position, and it makes that "thump" sound as soon as I'm 2-3 clicks away from "MAX COLD"
I am almost certain this means I have an obstruction on the Evaporator side of my Temp Door? Thanks again for your help
AnswerHi Frank,
Thanks for the progress report. I think you have it diagnosed, and it interesting that the door actuator appears to have recalibrated to a better position though it is hanging up which is probably why it went out of calibration. You might try removing the actuator and seeing what the door action feels like when you move it by hand. You will proabably want to do another calibration when you re-install the actuator.
If you would be so kind as to 'rate' my efforts I would be most appreciative (see below).
Roland
