BBlitz

Hi Everyone - We recently picked up a 2006 Silverado 2500HD Diesel and am having an issue with the climate system. I've done all the basic searching I can, and found several others with same symptoms, but they never seem to follow up with a fix.

When I have it set to 89 degrees or lower, it blows cool air...set it 90 (max) and it blows hot air. It's a dual climate system (both driver and passenger) and the only way to keep the interior comfortable is to swap back and forth between the settings continually, so I'd like to fix this. I've read a bit about stuck mixing valves and will try locating and messing with them this weekend...but they don't really seem to fit my symptoms exactly.

First, am I wasting my time working on this? I see posts referring to a Tech2 possibly being needed to diagnose/reprogram it. If that's the case, I'll just take it in to the local dealer, but I like tracking things down first myself when possible.

Second, I know the dealer installed 2 new batteries when they took the truck in on trade, and we had some exhaust work done afterward and they might have disconnected them too. It came with an aftermarket stereo (chimes don't work, etc.), but I haven't seen anything to indicate the factory stereo had any integration with the climate system so I don't think that's it. I mention all this because I'm not 100% certain as to whether it worked properly when we bought the truck, or stopped shortly after. We live in San Diego, so the weather is so mild that supplemental heat and cooling aren't usually necessary. I know when we test drove it, the A/C seemed to blow cooler, and the heat seemed to blow warmer...

Also, any recommendations on a good set of manuals and the best source for them? I usually buy the factory set for each vehicle I purchase, but have not yet done so for this one.

Thanks in advance for any helpful tips or suggestions!

Chevrolet Customer Service

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I am sorry to hear of your climate control inconvenience. I encourage you to take the vehicle in to be inspected by a certified technician. They will be able to offer a more accurate diagnosis with a physical inspection.

Please keep us posted.

If you have additional questions, please feel free to contact me.

Louis
GM Customer Service

snezthedog

BBlitz,

I have the exact same problem as you do. Its either Max Heat 90 or Max Cold 60. Any other temperature is something in between. Doesn't matter what zone you are in they both do the same thing. The fan works fine at all speeds. It seems like it would be something common between the zones. I am wondering if you ever figure out what the problem was.

Thanks

spongjim5

Both sides doing the same thing? What is your ambient temp showing on the control head? Have the dealership check the program that is in the control head and update if needed . Have them recalibrate all the hvac door actuators also. On the right hand side of the dash there is a triangle panel that pops off ,pull it off and check all the connectors and check for loose terminals . If the problem is still there ,you will either have a inside temp sensor,temp door actuators or control head. The actuators can do this problem ,they usually just blow full hot when on cold on either side or full cold when on hot. The control head usually has other symptons to go along with this. Temp sensors are in the dash vents and in the headliner right over the drivers head .I have never seen one go bad ,they just get noisy and make a scubbing noise. I would have it scanned first and then reply back here with all the codes in the Hvac system.
Hope this helps some.

snezthedog

Yes both sides do the same thing either full hot or full cold. Anyother temp seems to depend on what the temperature inside the cab is.

You said there is a temp sensor right above the drivers head? Is it round a little bigger than a quarter with holes in it? Does it look like a little speaker?

If that is it I may know what the problem is, I am an idiot. That thing was making all sorts of noise and was driving me crazy. I thought it was a little tweeter speaker that was blown since the truck I bought used has the bose radio in it. I unplugged it a while ago. I am not sure if the climate control was working prior to that. I will have to plug it in and check it out again.

spongjim5

That is the inside temp sensor . Take a canned air like to clean a computer key board and hold the impellar still,blow out the dust and then plug it back in. Do all this with the ing.switch turned off ,once you have done this start the truck DO NOT TOUCH hvac controls . Let the hvac run on for about five minutes this lets it reset everything. Try this and see how it works.

BBlitz

Nope, have not yet fixed my issue. I plan to have it checked the next time it goes in for a normal service. Living in San Diego with a mild climate, and primarily just using the truck when we tow our quads out to the desert, it tends to slip my mind. I will look into some of the info that spongjim5 listed though. Hopefully it's something as easy as that. Without pinpointing the problem first, my biggest concern is taking it in and they'll just recalibrate it, but still charge me for some expensive module.

johntaps

The small quarter sized 'speaker' above your head is a fan.....it helps circulate the air for the inside air temp sensor. When they go bad they give off an annoying whistling type noise. All the doors(including temperature) are controlled by electronic actuators.
You can also have a faulty control head (electronic) or a bad body control module
which would require programming by a dealer.

Best bet, bring it to a shop that has experience with this or you can end up changing parts you didn't need to change.

snezthedog

I think I have something else wrong with the heat control. Everything seems to work except I can't get any sort of mixed heat/cool. I think I am going to have to take it in. One thing I have going for me in Minnesota is that in the morning I need heat and afternoon I need cool, not too much inbetween.