No heater operation - blend door actuator location?

do the heater core hoses fell like they are the same temperatures. if so you do have circulation, they should be quite hot to touch, if this is so, it will be a problem with the blend doors not opening, check these and make sure you do have good circulation first.

The hoses are warm to a little hot and the same temperature. The blend door is brand new. I think there is a vacuum actuator in the glove box. It says if this is bad or the line is leaking, it will default to defrost and that is what it is doing. Your thoughts?

looking at Mitchell 1 it is a fully electric climate control system, a scan tool is required to check actuator operation and calibration, this can be function tested only in this model. i have been looking at a 2008 Jeep Liberty 3.7L engine Sport is this your model?

This sounds like a programmatic error which could be caused by a shorted blend door actuator I know you said you replaced some of them can I ask which ones?

Below is a diagrams to help us get on the same page.

Please let us know. I am interested to see what it is.

Cheers, Ken

Hi Ken, I replaced the blend door that has two actuators on it that is located just above the accelerator. One is on top and the other is on the bottom. They both work. Thank you

Yes it is 2008 sport with 3.7 l.

I would replace the mode actuator which is on the passenger's side.

Do I have to remove the dash again or can I reach through the glove box? Thank you,

Ken, here is an image if what I think is the mode actuator. This is right above the blower motor which is working on the passenger side. I can see it through the glove box. Is this it? Thank you so much for the help.

It is kind of hard to tell but it should be, It look like the same area the diagrams shows. When you remove the actuator manually move the door with the HVAC running that way you can tell which actuator does what.

Replaced the mode door still no heat. Ken, replaced mode door and recalibrated the blend door and still cold air

Can you grab onto the heater hoses after the engine is warmed up you see if they are warm? Here is a guide to help. Can you check the coolant level as well?

https://www.2carpros.com/articles/car-heater-not-working

Please let us know what happens.

Cheers, Ken

Yes they are very warm, Coolant is full. I think it is a blend door issue. My grandpa put it in and he is a good mechanic. I'm thinking calibration issue with the blend door

That could be. I would try to reset the system by removing the negative battery cable from the battery and holding it to the positive battery terminal for 5 minutes to discharge the system and let it relearn. If that doesn't work here is the reset guide from the manual.

Below

CAUTION: Do not exchange A/C Heater Controls from vehicle to vehicle. Software versions differ between models and model years. Installing an A/C Heater Control with software that is incompatible for a given vehicle can result in either improper or failed HVAC system operation.

A/C Cooldown Test

The A/C Cooldown Test:

is actuated with a scan tool.
tests A/C system performance based on evaporator temperature sensor input.
will fail if evaporator starting temperature is below 18°C (65°F) when initiating the test.
will pass if the evaporator temperature drops 11°C (20°F).
indicates test outcome by displaying one or more test status messages on the scan tool. These messages will clear after paging back out of this test function. Therefore, is it important to note all of the messages before doing so.
will cause the A/C status indicator to flash while the test is running.
Actuator Calibration Function

The Actuator Calibration function:

is actuated with a scan tool.
homes and repositions door actuators.
monitors for door span faults. Door span faults (XXX Door Travel Range Too Large or XXX Door Travel Range Too Small) will only display after calibration.
will cause the electric backlight (EBL) status indicator to flash while the test is running.

Please let us know what happens.

Cheers, Ken

Ken, thanks for all the help. We now have heat. The top actuator on the driver's side that attaches to the blend door was out of calibration.

Nice work, we are here to help, please use 2CarPros anytime. Can I ask how you calibrated it?

Cheers, Ken

I'll have to find out. I was out of town and my ex-father in law who is a very good mechanic heard that I was having problems and he looked at it while I was gone. I was told he recalibrated the actuator. I'll see if I can get more details. Thanks again.

That would be great so it will help others :)

Ok here we go, my step grandpa and his son replaced the blend door. Still no heat. I flushed the heater core, replaced the thermostat, flushed the radiator and replaced the actuator on the passenger side above the blower. Still no heat. I then replaced the control panel and still no heat. My ex father in law looked at it while I was out of town and found the wires for the two actuators on the driver's side were crossed up. I guess when they replaced the blend door, they got the wires crossed. Wires were switched and now we have heat. Thanks for all the help.

Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help

Cheers, Ken

Well, it worked for awhile and now it will get a little warm but not warm enough for these current Missouri Temperatures - 4 actual temp. I don't even know where to start.

heat at last finally heat at last! i had a feeling we still had air in the system, so we jacked the car up and bled the damn thing all day and night. you have to put the jeep on a tilt to get it all out. we did that before and it didn't work. i guess just didn't get it all the first time. it's working but really not sure how it keeps getting air in.

Glad to hear but the only way air can keep getting in is a leak up high in the system somewhere or you have a slight blown head gasket which pumps exhaust into the system.

https://www.2carpros.com/articles/head-gasket-blown-test

and

https://www.2carpros.com/articles/car-is-leaking-coolant

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

yeah, i heard about that. what kind of symptoms come with a slightly blown or blown head gasket, besides exhaust in the system? if there is a leak up high, it must be really slow because i can't find it. i have a feeling it is going to happen again. thanks.

When I first turn on my heater it blows hot air for abut a minute or two then it blows cold air . What do I need to check to solve my problem?

I need you to check a couple things. Do the following: with the engine cold, confirm the coolant is full in the radiator. If it is, start the vehicle and allow it to warm up to operating temperature (make sure it is warming up to operating temperature) with the heater on high. When the heat stops and becomes cold, open the hood and locate the two heater hoses which go from the engine to the firewall of the vehicle (heater core). Feel both hoses. If one is hot and the other cold, you have a plugged heater core. Let me know what you find.

Here is a video showing all the things which can cause this problem:

https://www.youtube.com/watch?v=SNRb6pSwYuU

My heater is not working correctly you can feel heat coming out of the vents on the first notch and a little bit on the second after you move it up further it blows out cold air. The coolant level is fine my car does not overheat to as far as I'm aware the thermostat is fine and when you touch me heater core it's hot. In the air conditioning works fine with all the vent I have been told so many different things I was told I need to flush the heater core, it could be the heater switch that controls it and I was also told I can be the vent relay control console. I'm just wondering if you have any ideas. another thing that happened is yesterday when I got in the car nothing is coming out of the vents when I would turn the knob I could hear some clicking like from underneath the dashboard. don't know if that's related not. that help when I restarted the car everything was fine. please help I don't have a lot of money to be putting in to checking everything. also if I had hooked up to one of those computer machines would that be able to tell me what it would be?

Hello,

The clicking is a clue that the temperature blend door actuator is not working correctly. Here is a guide to help you step by step with instructions in the diagrams below to show you how on your car. Turn the system on so you can hear the noise then use your hand to feel which actor is making the noise.

https://www.2carpros.com/articles/replace-blend-door-motor

This guide can help as well:

https://www.2carpros.com/articles/car-heater-not-working

Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.

One more question that had been the only time I have heard the clicking noise and it was when I turned the nob to the settings to the heat temperature besides that time i have not heard it. Do you still think that's the problem? There has been times that nothing has been blowing out at all then I restart the car and it is blowing. Just wanted to make sure u still think that's what it is. Thanks for your help.

Yes it does sounds like the actuator is broken and making the noise which needs to be replaced to fix the problem. Can you please shoot a quick video with your phone so we can hear the noise? that would be great. You can upload it here with your response so I can be sure.

Yes I can. i have but not heard the noise in a few days. This morning nothing was blowing out of the vents or would start blowing then stop. As soon as I hear it again i will send a video think i will go ahead and try to fix that piece seems simple enough.

Was the air blowing all the time before and this problem just started? Sure sounds like the temperature blend door actuator is not working correctly.

Last year it would stop blowing but then stopped after doing it once or twice, but my heat would come out fine. Now it rarely stops blowing but there is barely any heat and the air works great.

Okay, it sounds like the blower motor might be going out which is common. here is a guide to help test the motor and show you how to check the power and grounds. The heat will still be the actuator.

https://www.2carpros.com/articles/blower-fan-motor-works-on-high-speed-only

Check out the diagrams (below). Please let us know what happens.

Heater is blowing cold air, ac works fine. No leaks or fogging, just blowing cold air?

Hello,

It sounds like you have a temperature blend door actuator that is not working here are two guides to help walk you through the steps of changing it with the location in the diagrams below to show you how on your car.

https://www.2carpros.com/articles/replace-blend-door-motor

This guide can help as well

https://www.2carpros.com/articles/car-heater-not-working

Check out the diagrams (Below). Please let us know what happens.

Thank you for this post I got a new actuator everything works again FYI.

Changed the thermostat, purged the system, verified blender door is working. The heater core has been flushed and has no restrictions.
I took the hoses off the heater core with the heat and car running and have no coolant running into the heater core. What would be the cause of no coolant to the heater core?

Good afternoon,

If you have no flow to the core, then you either have clogged hoses or a bad water pump.Was the coolant level topped off when you removed the hoses?

Does the car overheat?

Roy

1. Disconnect negative battery cable.
2. Drain cooling system See: Cooling System > Procedures > Cooling System - Standard Procedures.
3. If water pump is being replaced, do not unbolt fan blade assembly from thermal viscous fan drive.
4. Remove two fan shroud-to-radiator screws. Disconnect the coolant overflow hose.
5. Remove upper fan shroud and fan blade/viscous fan drive assembly from vehicle.
6. After removing fan blade/viscous fan drive assembly, do not place thermal viscous fan drive in horizontal position. If stored horizontally, silicone fluid in viscous fan drive could drain into its bearing assembly and contaminate lubricant.

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7. Remove accessory drive belt (1) See: Drive Belt > Removal and Replacement > Accessory Drive Belt - Removal.
8. Remove lower radiator hose clamp and remove lower hose at water pump.
9. Remove seven water pump mounting bolts and one stud bolt.

CAUTION: Do not pry water pump at timing chain case/cover. The machined surfaces may be damaged resulting in leaks.

10. Remove water pump and gasket. Discard gasket.

Not getting heat. had thermostat replaced system flushed heater core back flushed worked about one month. no sign of antifreeze leaking in car or smell of antifreeze. mechanic said it may be the heater core. any other ideas of what it could be before I have it replaced?