Question about Cars & Trucks
Chances are the electronic/digital HVAC control unit is bad. This same problem happened to me and I had to replace the entire unit. The dealer wanted to charge $800 for just the part! After I freaked out on them, they found a used one for less than half. Sorry, but there's no easy fix here.
Posted on Jul 19, 2008
when your car is in defrost it has an ac cycling it removes the moisture then sends the air over the heater core depending on how warm you set it you can feel warm or cold but the ac is always cycling...ridding the moisture...you need a good ac tech it will be okay...its just expensive going into the heater core if needed...!
Posted on May 07, 2009
There may be a couple of items to look at here.... but the most common problem is a source of vacumn to the pneumatic operation of the heat/a/c vent doors....if vacumn is not distributed properly to the vents you command it is assumed that there is either no vacumn to the selector swith panel(broken vac. line,kinked vac. line, defective in dash a/c control panel) or under the hood a defective vac./heater control valve that is stuck,frozen, not allowing the vacumn to pass through it to supply the indash pneumatic controls and/or panel.
Most vacumn systems that i have ever came in contact with incorporate a vacumn supply tank(nothing more then a round plastic vac. resevoir) which is used in sequence with the a/c heater controls, its purpose is to keep an even vacumn supply to all command points continously while the vehicle is being driven, without this supply one will experience the a/c coming from various different non selected dash vents upon acceleration, this is a direct relation to the tank either being defective(leaking vacumn) or its supply hose(usually vey tiny rubber/plastic tubes) being pinched or broken not allowing the vacumn to the supply tank.
listen for vacumn leaks(hissing sound), look for the obvious...broken vacumn lines or hoses, also check for a defective one way vacumn valve on some pneumatic controlled door vent systems(these valves are inserted in a vacumn line one side being the ""in" port and the other side of it being the "out" flow port,typically if these dont work the vents will also devert your a/c or heat all different ways through your dash.
to check these valves, simply remove from the vacumn hose, and apply vacumn to one side,if vacumn flows through the valve, apply the same vacumn to the opposite side of the plastic valve, if vacumn flows through on the opposite side the valve is bad, it should only allow flow from one side not the other. These valves are small and are usually white or black plastic and look like the old vacumn dash pots used on the old carbureated engines only smaller with one small hose in and one small hose out.
Posted on May 20, 2010
check your blower hoses to see if one or more have come loose or got redirected or the selector switch isn't functioning properly (is it blowing better on defrost as opposed to floor vents, or forward vents, etc.)
Posted on Oct 26, 2010
Tips for a great answer:
Dec 28, 2014 | 2010 Jeep Liberty
Aug 05, 2014 | 2010 Jeep Liberty
Jul 16, 2013 | 2010 Jeep Liberty
Apr 16, 2013 | 2010 Jeep Liberty
Jan 03, 2012 | 2010 Jeep Liberty
Nov 01, 2011 | 2004 Jeep Liberty
Dec 08, 2010 | 2006 Jeep Liberty
Dec 25, 2009 | 2002 Jeep Liberty
30 people viewed this question
Usually answered in minutes!