Climate control potentiometer part?

Hi all, I'm having issues with the temp control where it keeps defaulting to warm. Almost certain it's the potentiometer, I've even taken the whole unit apart and cleaned it with IPA which helped for a few months. It's the 2001+ climate control. Looking for a more permanent solution. Does anyone know what part this is? I'd rather not buy a whole climate control unit just for this part.

Thanks

 

If it's like the 04 good luck trying to find one. I couldn't.

 

I've been having the same issue. Have the a/c on and it randomly goes to hot air. I can push hard on temp control knob and it will go back to cool, sometimes it will never mess up again for awhile or maybe last a hour. Asked about it on here before but no help. If you figure it out let me know.

 

turn the knob from one extreme to the other about 50 times. Seems to straighten mine up for awhile.

 

seriously at this point I'm ready to try about anything. wouldn't happen to know what year the climate control would change out with? just saw where a guy has a 99 and a 98 that is going to scrap yard. motors, tranny's whole 9 yards. was thinking about getting the climate controls. One is a 4-runner.

 

The older model years have mechanical levers and cables. I think the 2001-2004 are of the type you'll need.

 

Yea starting in 2001 they changed the climate control. This issue is due to the wiper of the potentiometer getting dirty, and because of this it is always providing high resistance feedback to the climate control computer. The high resistance happens to be the heat setting, which is why there is always hot air flowing. I pulled my unit apart and tested this with an ohm meter.

As for a solution, yes the turning back and forth a bunch works for a bit, as does taking the unit apart and flushing the potentiometer with IPA. Unfortunately these are only temporary and I'm looking for something more permanent.

I'm going to talk to a guy at work to understand what material the potentiometer wipers are made of and see if I can understand a bit more about what's going on. The pics mechanicjon posted are of the part I'm discussing, but I can't find that on digikey. I'm wondering if it's possible to actually disassemble the potentiometer unit and fix the issue

 

I've taken it apart and cleaned it. The problem is the carbon resistor is silk screened on the board. Once it wears out theres nothing left.

 

I looked everywhere on the internet i could for a week with no luck. I usually pretty sucessfull and finding stuff. Ask @BartMaster1234 he knows my google skills.

 

I can vouch for Jon’s excellent google-fu.

 

@mechanicjon did you ever look at the ones for the toyota highlander? somewhat expensive but looks to be the same type of pot.

https://www.carid.com/dorman/hvac-control-module.html?urlId=10466906

 

I bet that would work. You'd have to de-solder it from the little board it comes with.

 

True but since you can purchase this part means that the pot is potentially still manufactured. So the one that you took off your circuit board, I'm assuming based on your above picks, it didn't have any sort of manufacture info/emblem or any type of part numbers?

 

Has anyone taken any electrical measurements on the pins? A pot is normally 3 pins, that one might have a couple switches built into it I guess.

 

No markings or numbers on the outside. Here's what the inside looks like. It has 4 wiping arms.

 

I did take measurements on it, once I'm back at work I can check my notes and update. It has many pins (7 I think?) But only three are used. I suspect the same part package is used for many different parts (like a 6 position switch or something)

It is worth noting that in the same time period, Toyota was also using what I believe is a multi position switch for temp control. I have a 2003 Celica and the temp knob has discrete steps. I might try to take that apart and see what part is in there. This switch could easily be rewired to work with the circuit setup in the Tacoma climate control, and might be easier to find

 

@brian1649 that is very interesting if only 3 of the pins are used. Based on the measurements you might just be able to replace it with a normal pot that is of similar size.

 

I have been using CRAIG products for years with good results. Haven't used DeoxIT Fader before but looks like something to try.

$38 DeoxIT Connector & Contact Treatments

https://www.amazon.com/dp/B01AQ7FZFG/ref=sspa_dk_detail_6?psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFNMkpKWEdER1E5Q0gmZW5jcnlwdGVkSWQ9QTAwOTY0MDIxTEdFVDdNUTdUWFhJJmVuY3J5cHRlZEFkSWQ9QTAzOTczNTYzOE1VNzdMRkMzSTUwJndpZGdldE5hbWU9c3BfZGV0YWlsMiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU%3D

 

Alright following up on this with my notes from testing:

I found that (counting from left to right with looking at the potentiometer from the pin side, shaft sticking up) pins 2, 4, and 7 are used. This also ended up being super obvious because those are the only pins that are connected to traces on the PCB. I found that pins 2 to 7 were the fixed resistance, and pin 4 was the wiper output (not totally sure about the correct terminology there, feel free to correct me). The pin 2-7 fixed resistance was 2.7kOhm. Prior to moving the potentiometer back and forth many times or cleaning it, I found that the pin 2-4 resistance + pin 4-7 resistance ended up being higher than the pin 2-7 resistance. What that tells us is that there is added resistance through the wiper arm (likely at the contact point).

Once I moved it a bunch and cleaned it, when turned to the hot position it had a pin 2-4 resistance of almost zero, with a pin 4-7 resistance of 2.7kOhm, and when turned to the cold position it had a pin 2-4 resistance of 2.9kOhm and a pin 4-7 resistance of 0.2kOhm (so maybe still a little dirty there?).

I don't know if this helps us at all. Man would I like to track down a new part for this though. Maybe that deoxit product will work

 

let us know. the rapidly moving back and forth didn't help me at all. but I can push on the knob (pushing into the dash) and it will change instantly.