I have a 2003 Hummer H2 and if I wanted to change the temperature in my vehicle, I would do so by turning the knobs on the vehicle's climate control module. One of which is for the driver side while the other is for the passenger side. A picture of the module is shown below...

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The problem is that when turning either of these knobs results in value for the target temperature to jump around in either direction. For example, if I had the temperature at 65 degrees and decide to turn the knob to the right to make it warmer, it may first immediately jump to like 71, then 64, then 61. Usually it just goes all the way down to 60 when trying to make it warmer. For me to actually make it do what I want, I have to actually push or pull the knob and turn it increment by increment for it to head in the direction I want it to. But even then I struggle with it. If I can, I would rather fix the knobs rather than replacing the climate control module.

From what I read so far, these knobs would be called rotary encoders. And everytime you turn a rotary encoder, there is a single step up or step down in value depending on the direction you turn it for every increment. The problem with these rotary encoders is that there isn't single step up or down in value depending on the direction turned. The value jumps around and is not consistent with the change in inputs. So I guess it is some sort of bad connection.

So what's happening that's causing this issue and what should I do?

  • I don't know if it would help, but there's a way to reset the entire system by pulling the fuse for it. I don't know which fuse it is off the top of my head, but I'm pretty sure it isn't hard to figure out. I did this on my '06 Silvy with the climate control for a different issue. Worth a shot. If that doesn't work, you might need to have the dash module replaced. These are guesses, so leaving as a comment. Sep 17, 2020 at 14:24
  • Unplugging the battery for 10 minutes or so would accomplish a reset as well if the fuse is unknown, wouldn't it @Pᴀᴜʟsᴛᴇʀ2?
    – GdD
    Sep 17, 2020 at 15:30
  • 1
    @GdD - The process I'm talking about to reset it is to pull the fuse, then turn the key on, letting everything cycle, then turn the key off, followed by re-inserting the fuse and then turning the key back on. It requires the cycle in order for the reset to occur. Sep 17, 2020 at 16:08
  • @Pᴀᴜʟsᴛᴇʀ2 Sorry about getting back so late. I was doing a major repair on the vehicle during that time and forgot about it for a while after that. Unfortunately the reset didn't work. I pulled the fuse off, started the engine, and saw that the module was off because the fuse was out; put the fuse back in, started the engine, and saw that the problem still persisted. So the problem seems to be mechanical dealing with either the knobs or a bad connection. I was hoping someone knows about how rotary encoders work and shed some light because I think this may be the underlying issue. Nov 2, 2020 at 4:39


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