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Chevy S10 - GMC S15 and Sonoma Climate Control



  • hello im having problems with 2001 s-10 .as the heater works great .but controls will not change from floor to defrost .it blows out both floor and defrost all the time no matter where i have the control. could this be the .control knob or a vacum issue i noticed there is 4 vacum assy . i think it is not the temp control.control. o took glove box out i can see it working ok all though i see a vacum ball right there in same area. that seems as soon as i start the egine . it pulls all the way open ? i have no clue to go from here . i do see it looks like 2 vacun balls down by floor on drivers side .. can any one help thanks bill b.
  • the_big_althe_big_al Posts: 1,079
    I think you have a stuck baffle somewhere. I know on my truck, also a 2001, it takes a few seconds to switch from mode to mode. It will take several seconds to switch to defrost and then back to dash vents and then to floor vents. I think it is because the baffle that directs the air into each location is sticky. I don't know where this is or how to fix it, but I think that might be your issue.
  • I have the same problem with my 2001 GMC Sonoma. Plus the blower (or something associated) starts sqeeking - especailly if I make a right-hand turn. Pretty weird! Perhaps the blower motor resister for the fan not working in first two postions and a drop of oil on the motor shaft? Is any of this halfway easy to get to?
  • I have a 2003 Chevy S10 with heater control problems, the heat will not switch from dash to floor or from dash to defrost. I tried looking up under the dash to see if I could see the control arms but everything is covered up.Any advice on how I can get to it to see if the flapper is stuck?
  • Did you fix this yourself? If so, what were the part #'s and how much did it cost? Where did you buy the parts? Thanks
  • dlt1558dlt1558 Posts: 1
    edited July 2011
    I was replacing the fan switch in the control module and the plug that allows me to switch from floor to dash vents came unplugged. I cant seem to find where it plugs back into.... Any help would be appreciated. This is in my 92 SLE
  • On my 1990 S15, it seems like the volume of air coming out of the vents is extremely small. When the fan is on setting 1, there is almost nothing coming out of the vents. When it's on full, there is very little air coming out. Also, the floor vent is always open no matter what setting I have it on (Max A/C, Norm A/C, vent, HTR) and there is more air coming from the floor vent than there is from the dash vents. I'm assuming all the doors work properly because I can hear them moving. Someone told me that this is how these trucks were made, I don't believe this.
  • mrrosemrrose Posts: 1
    It is behind the glove box. Open the box and the stop is spring loaded so you can push it out of the way. be careful as all glovebox contents will spill on the floor.
  • I have a 98 Blazer with AC, i can not controll the tempeture it is on high heat all the time, the AC/heat controlls work fine but i can not turn off the heat with the tempeture controll knob. Thanks for any help. Sulley
  • gonogogonogo Posts: 879
    4/09 wow. Most likely blend door motor is bad. You can try pulling the HVAC fuse or disconnect battery to see if it just need a reset.
  • taber33taber33 Posts: 1
    edited March 2012
    I have a similar problem with my 2000 Sonoma, but instead of it being stuck on one set of vents it is skipping over the floor vents n goes right to defrost... How could I fix this?
  • The blower in my 2004 GMC Sonoma has stopped working, that is, a couple of weeks ago it started to make clattering noises at the highest speed, now there is no "fan running noise" and no air pushing through at any setting, although there is warm air being produced (I want to defrost my windshield). Does it sound like something a novice DIYer could take on? Where should I start?

    Thank you!
  • Bet you have a vacuum leak. Your heater is controlled by vacuum, and acceleration will give you more vacuum. There is a bundle of wires that come through the firewall, about center, down 9" or so from top of it, in that bundle is a vacuum line. If it's hooked to thin air, or you have a rotten vacuum line in your system, you'd get that effect.
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