I had the same symptoms until I didn't; that is it simply quit all-together.
Years ago I replaced the Blower Motor Regulator and that worked for about 4 years. Today, there is no fan (again, it was erratic for a while, then it stopped).

Moving forward,
1. I am a good w/electronics and solder, so I did the repair you suggested replacing the 47K rheostat with new. - no improvement.
2. I installed a second new Blower Motor Regulator, at the fan. No Improvement. The unit was very warm when I removed it after only a few minutes testing.
3. I removed the new Regulator and also the fan, did a 12VDC bench test on the fan motor and it ran well, nice a smooth.
4. I tested the readings on both regulators, the old one did not match the new one, but there were no dead shorts.
5. Lastly I tested the pins (Car Side) at the Regulator, found good steady voltage on RED/BLK and variable voltage on center pins when rotating the fan speed ****...

I am clueless on why this thing will not run.
Any thoughts?

 

I had the fan quit working but it started working again after hooking it up to 12 volts and reinstalling it. Depending on it's age and use the brushes may be too worn out and you may want to order a new fan. Also, the potentiometer replacement may not be exactly correct. If your a/c light turns on when turning up the potentiometer i would guess it is ok though. You may want to use electrical cleaner on the blower parts and run it a bit more on 12v and reinstall it and see if that works.

 

Good thoughts Brasstacks2, thanks.
It did exactly that. The Fan worked after reinstallation with the original Regulator and the light come on when **** is moved.
However the Recirculation selection does not appear to function, the light comes on when selected but the fan doesn't change speed. I didn't blow it out with cleaner, I will access it and do so.

Thanks for the PDF on the Board connectivity. Not Being familiar with it, I didn't realized they were hard connected and should come out together. When I removed the front of the unit, the two boards separated w/ease. I assumed they just "unplugged". I will take the controller back out and reconnect the boards with epoxy as you suggest.



- D

 

The recerc button does not automatically operate the baffle system to circulate the inside air, it depends on the ambient temperature and a few other reported sensors that are programmed into the button's operation. It is hard to know when the recerc function will kick in, so give it a few different tries when the problems with the fan speed is resolved (your just working on one thing at a time and the recerc may not be a problem as of yet).

Also, just to remind you, the two 'rods' behind the A/C head MUST be correctly orientated within the receivers behind the A/C head. I believe they are slotted and only insert one way but again, they MUST be connected before the correct air directions can be realized. This is given only if nothing inside the air box is broken. Good luck!


.

 

tried to separate my HVAC control module to get into the circuit board and clean everything. When the two parts separated, the horizontal board remained in the housing. How do I get it out?

 

See attached PDF of this fix. There is a locating pin that is supposed to hold the horizontal board in place. If another Crossfire Owner previously did this DIY Fix, there may be some glue applied there that has the board secured to the housing. This DIY fix corrected my erratic HVAC module erratic operation, along with a new Blower Motor Resistor. (Note: After I did the circuit board fix, when I tried the system once it was all put back together, same erratic operation. I then replaced the Blower Motor Resistor and the HVAC operation was back to as new.)

There is also a recommended DIY fix that addresses the small potentiometer that sits behind the control ****. This could also be the cause of your erratic operation. Jury is still out on which fix solves the HVAC erratic operation. I'm a believer that there are 3 possible faults:

1) Circuit Board Connectivity
2) Defective Potentiometer
3) Blower Motor Resistor

 

Thanks! That did it!

BTW, are the temperature wheels illuminated?

Also, can you replace the lights in the push buttons in the center of the Control Module?

 

I believe the Fan Speeds & HVAC Settings do light up when the lights are turned on, along with the push buttons in the center. As to whether the bulbs can be replaced, I think I remember that as not a possibility.

 

Yes the bulbs can be replaced this has been discussed before. Finding the correct bulbs is another story.

 

Hi All,
I've have the erratic blower fan issue for a few years now, and I've finally gotten around to fixing it. I've remove the boards from the housing, and separated the horizontal board from the vertical board. I would like to replace the potentiometer since when I measure the resistance across the terminals, **** position 4 and 5 read open, and positions 1, 2, and 3 fluctuate. I don't seem to be able to separate the vertical pcb from the front trim plate. I hold back the tabs, but the temperature control ***** seem to be holding it in. Does any one know the trick to getting that board out? The pdf's that have been posted don't show how to replace the 4k7 potentiometer, they just talk about replacing it. Found this website describing how to remove the vertical board: https://www.benzworld.org/threads/w2...bulbs.2141945/ - you have to de-solder the temperature control pots.
Thanks, sincerely
-Jerry

PS. I was able to buy 5x 4k7 potentiometers from ebay for ~$7 with free shipping (https://www.ebay.com/itm/235043299378?var=534980590605). They seem to check out using my DMM - few ohms to 4.7kohms.
PPS. I just saw another post by RyanB from 8 years ago that said the white plastic hex inserts on the side that go into the temperature control wheel ***** pull out, and no desoldering is need. They didn't budge when I tried to pull on them. I didn't try very hard, so I can't verify. The desoldering was very easy, but pulling the wheels out would've been easier.

 

Your recirc rocker switch may be actually working. Its for when the car is Off, and not running I believe, acts to recirc air and ? heat while the actuator door behind the glovebox is open ; look at service manual about this; its kind of confusing and seems like an unhelpful feature the way it is described there.

 

have any more of these. I know its been a year or more. If so, tell me how to send you $

 

You can get the potentiometers here. Check the specs to make sure this is the correct one.
https://www.digikey.com/en/products/...20-E-S/9556014

Credit goes to pizzaguy for his original post. I booked marked the page for the pots thanks to him.

 

Thanks so much for your time! Assume the shaft from the present **** goes in the slot of the face of this pot. Maybe this will make the blower switch less "jittery". A vexing problem. I have a new resistor element for blower too, but I don't think that's it....
This HVAC aspect, of an otherwise very reliable vehicle is an incredible timewaster.... Ive just given up on replacing the vacuum actuator behind the glovebox for the fresh air door, which squealed annoyingly from a vacuum leak in it's rubber diaphragm. One absolutely cannot reengage the new actuator arm's 4mm hole onto the detente nib/*** of the spring- loaded door , without pulling the entire dash , airbag etc. ( a 2500$ shop job)....I dont know how anyone actually did this....( I was lucky to even locate a new part, unbelievably)...You can frustratingly see the hole in the arm go over the nib, , but theres no way to engage the small hole onto the *** itself while twisting and relocking the vacuum element onto its plastic base on the blower box! Going to leave the door jammed open, and the actuator nonfunctional. Hell with it!! At least its quiet in the cabin.
Thanks again!- m weiss

 

THose are the ones I order. Their "inner hole" is shaped to fit the shaft of our fan control ****-thingy.

 

It sure will. In almost all cases, this is the fix for that. I order 10 or 12 pots at a time, I am on my third order and only one person still had erratic fan speeds.
When they looked into the cavity, the fan motor had been getting wet and was about destroyed.

If you car is not sitting outside with leaves all clogging up the drains, your motor is fine.

 

Well- about 15 years ago, I had water into the passenger well, and it was the drain hole clogged under the windshield plastic dam with debris ; The car does sit outside, and about 5 yrs ago I had prophylactically removed the wipers, sub-windshield plastic dam, and cleaned things out. I need to do it again, but try to keep debris out of the grille area above the 'dam', on a daily basis... The blower area now is dry, and so's the cabin, so I suspect the resistor is ok; easy enough to change it out at this point, I still have everything out for my aborted vacuum element repair.... I will try the new trimmer/potentiometer . Is there a writeup anywhere on removing the vertical PCB that the pot is soldered to? Ive seen some talk of removing the thermostat wheels on either side, and the hex-keyed white plastic struts that they attach thru to their pots. There appear to be a dozen small plastic tabs that lock the PCB in place, and the front control ***** of course need to be pressed off the front of the board. I just hope I can figure it out without damaging anything.
Thanks again for the feedback and information- mrw

 

I updated my reply to give you credit for providing info for the pots.
Thanks to you pizzaguy, I had bookmarked the page for said pots from one of your threads.

 

Are there instructions for removing the board with the pot from the controller. I have been searching and posts saying it was removed are frequent but no how to. Can anyone help?