2008 Jeep Liberty sport no heat on driver side?

I noticed that on my driver side that there is no heat blowing through the vents, the air is cool coming through the vents, however on the passenger side it blows nice and hot.  I went through the process of flushing out the heater core, I reversed flushed it as well and saw quite a bit of gunk that came out.  Before I put everything back together I ran coolant through the heater core.  I started my car and turned the heat on full blast and still got the same symptoms.  I put the dial on all the options, (floor,defrost, etc.) and it worked just fine, I put it on ac and it worked fine, I put it back on heat and still got the same symptoms I started with.  Any suggestions or advice is greatly appreciated 

6 Answers

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  • Bort
    Lv 6
    3 weeks ago

    This doesn't have anything to do with the heater core.

    Blend Door Actuator. There are several of them under the dash that are activated and control where the air is sent according to where the vent selection knob is put (defrost, defrost and floor, floor only, floor and interior, etc). It's probably the actuator that opens the vent door to send air to the drivers side. One actuator works both heat and ac so you'll have to find which one it is that's not working right.

    BDA Location:

    There are several of them because there's several in the vent system. Since it's easiest remove the glove box and the panel under it. This is what they look like:

    https://www.autozone.com/parts/cooling-heating-and...

    As I said there are several of them. I would pull the furthest one from the passenger side door because that makes the most sense of which one is malfunctioning to test it. I recommend using alligator clips on the wires but hook 2 wires to each terminal of your battery. There are 2 terminals on the actuator. Clip the wires to each terminal of the actuator (do not touch the wires together!). There is a stem on the actuator that should turn...to turn the vent door.

    Flip the wires on the actuator around (it works both ways). If it doesn't move at all that's the broken one.

    It could also actually be the vent door that's stuck but since AC works on the drivers side the door is working.

    If all the BDA's work it might actually be the vent selector potentiometer ("pot") - the knob that controls where the air blows out. In a 2008 Jeep WK (Grand Cherokee) you can pop the interior plate with the heater controls on it out by:

    1: At the bottom inside that little compartment is one phillips screw you have to take out.

    2: I use a flat head screw driver and start at the top center vent in the corner by the steering wheel and that whole thing pops out. Do it gradually, pop one side, then the other side in the same place to prevent cracking or breaking it.

    I would first turn the ignition on just before starting it and use a test light to probe the terminals on the vent selection switch. You should get power from every other terminal at least (one might be a ground for each vent setting).

    Me? In my personal 2008 Laredo if I couldn't find a bad BDA I would just replace the switch instead of messing around with it because if the BDA's all work the only thing left is the switch. Thought I'd include how to test it if you didn't know how just in case you wanted to be thorough.

  • Jason
    Lv 7
    3 weeks ago

    Does it have automatic climate control where you can set the driver and passenger side to different temperatures? If so, then you probably just need a blend door actuator on the driver's side. Simple to replace if you don't already have back problems. 

    • erik3 weeks agoReport

      It doesn’t have climate control, just one set of controls.  

  • 3 weeks ago

    You may have a bad drivers side blend door actuator on the heater box.

    Do a search on youtube for replacing the blend door actuator for the drivers side and find out if the actuator is turning when you turn the heat control form cold to hot.

    do a search for no heat on drivers side to find out if a plugged heater core is common.

    Another mechanic I know puts a couple of foot long heater hoses on a heater core and fills the heater core with CLR to try and break loose gunk inside the heater core. Auto parts stores also carry a heater core flush product you might want to try

    Source(s): Mitsubishi Master Tech
  • Anonymous
    3 weeks ago

    It has nothing to do with the heater core and has everything to do with an airflow problem. Check the ducting, air diverter or "blend door". 

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  • L.N.
    Lv 7
    3 weeks ago

    The blend door actuator isn't working. It has nothing to do with the heater core. There is only one heater core and it provides heat to both sides. The temperature is controlled by the blend door that mixes varying amounts of cold air and hot air to make warm air to your preference.

  • Ron
    Lv 7
    3 weeks ago

    A blend door or a vent connection is not working

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