Strange servo/motor sound when adjusting temp climate control

Over the last few years my truck has been developing an annoying servo / motor sound when the temperature climate control is adjusted. At first, it would happen just when it was adjusted to all the way hot, so I would just move the dial a small amount until it would stop, and as time has gone one, it happens constantly no matter what setting the dial is on. It sounds like a servo is moving back and forth or limit to limit constantly at this point.

I'm going to dig into the dash either this weekend or next weekend depending on how other truck rehab projects go. So more just wondering if this is a known issue (and I am just not searching for the right keywords) or if I am venturing off into un-charted territory.

 

Here are some threads that talk about these servo motors. I didn't read through all of them but they are all about the motor making noise.
I posted a good video in one of them about how to diagnose & replace problems with them.

Welcome to TW

https://www.tacomaworld.com/threads/strange-sound-electrical-relay-servo-under-glove-box.692911/
--> https://www.tacomaworld.com/threads/climate-control-unit-replacement.714929/
https://www.tacomaworld.com/threads/heat-and-then-no-heat-then-heat.697573/#post-24997661
https://www.tacomaworld.com/threads/help-identifying-this-noise.687268/
https://www.tacomaworld.com/threads/anybody-know-what-this-is.678939/#post-23905587

Also it seems it's been hit or miss for some on getting it to go away. Good luck!

Could be a bad sensor, motor, dirt, circuit board.

 

Sounds like the blend door actuator. It seems to be a common issue. There's a servo motor that controls a door that determines the mix of hot and cold air. When you turn the temperature dial it moves the servo. Mine is starting to go bad, ocassionally after setting the temp to full cold, it will drift back into blowing warmer air. Cycling the temp control from hot back to cold is a temporary workaround as they start to go bad. If yours is making a lot of noise it's probably time to replace it.

 

Thanks for the replies and links to the previous threads. I'm glad others have figured it out. I'll pull everything this weekend, and give it all a clean/regrease and reinstall..

And thanks for the welcome. I used to be a heavy contributor on TTORA (20 years ago), but those boards seem to be dead, so it's nice to see that there is still an active 1st gen forum community.

 

Post attempted fix update- I didn't give myself enough time to work on just this issue. I was able to, however, locate the actuator, and remove at least two of the screws holding it in place, but I wasn't able to free it from its place. It appears to be different in my truck than the videos posted in the linked posts. I was able to remove the climate control unit and use CRC electrical contact cleaner on the connections. Between removing the two screws on the actuator, and cleaning the back of the climate control unit, it has at least stopped the constant movement of the actuator. So.. until it acts up again, I'm crossing that off my list and moving on to bigger fish (valve cover seals).