Issue with heater/air blowing controls

2008 JEEP LIBERTY
168,000 MILES • 3.2L • V6 • 4WD • AUTOMATIC
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SHACKLER555
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  • 2 POSTS
My daughter has the vehicle listed above that has given us some problems in regards to the heat/air controls (this has auto controls). The knob that controls the speed doesn't work, the speed is basically nothing at all. It used to just work on high, now nothing. I just replaced the Blower Motor Resistor and now it only blows on high constantly and does not even turn down or off and the knob for changing positions does not seem to work either (it did work before-hand), but the blower itself does work. Not to mention when I took out the old resistor it was for a 2010 Jeep Liberty. Very Strange. I thought about looking into the Blower Motor Relay or Fuse but can't seem to locate it? Maybe not.. I wish there was an YouTube video out there for this year on this topic.
Nov 18, 2019 at 2:39 PM
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MASTERWRENCH
  • ✓ASE Certified Mechanic
  • 258 POSTS
  • ASE Certified Mechanic
It sounds like the HVAC (Heating Ventilation Air Conditioning) control head is not responding and is most likely offline. When this happens, the default state of the HVAC system is typically blower speed set on high and the mode set to defrost. Let's start by checking the fuse for the HVAC controller. The fuse you'll need to inspect is M34 in the fuse box under the hood. See the attachments for fuse location and system wiring diagram.
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Nov 18, 2019 at 8:45 PM
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SHACKLER555
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I checked the M34 fuse and it looked fine but I replaced it anyways and nothing changed. Like you said, it's stuck on blowing high on the defrost mode. Any other suggestions?
Nov 19, 2019 at 9:20 AM
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MASTERWRENCH
  • ✓ASE Certified Mechanic
  • 258 POSTS
  • ASE Certified Mechanic
At this point it sounds like the HVAC control head has most likely failed and will need replaced.

Let me know if that resolves the issue.
Nov 19, 2019 at 7:17 PM
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