Heater blowing cold air

So you are hitting on the two common causes of this. Here is a video that will give more info on this issue:

https://youtu.be/SNRb6pSwYuU

I would suggest we start with access the blend door and remove the actuator (they call it an AC radiator servo #2) and move the door manually to make sure the heater blows hot. It sounds like the heater core is operating as the lines are hot so that is a good sign. With the other info on the blend door I would start there. Let's run through this and let us know what you find. Check out the diagrams (Below). Please let us know what happens. Thanks

My heat blows cold air and unable to defrost car properly. I am curious to know if the blend door is located where it can be easily accessed to be replaced. Heating /AC blend door actuator location

It sounds like the temperature blend door actuator (servo motor) is not working correctly here is the location in the diagrams below.

this guide can help as well


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

Also, what temperature is the coolant reading? If it is not warming up properly, then that will cause the heat to be cold. Have you checked the heater core hoses? There are two hoses that come out of the engine and go to the firewall. These hoses are always right next to each other. If one is significantly hotter than the other after the engine is warmed up.

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

Hello,

I found this diagram for a 2011 it might be the same. Air blend door servo motor. Check out the diagrams (Below). Please let us know what you find.

I warm my car up, the heat never comes on. I went to PepBoys and they diagnosed it as an issue with the blend door. I spoke to a repu man and he said that it could be stuck and that my car is too new to have an issue with the blend door.

Parts go out all the time so the car being "too new" has nothing to do with it obviously because it is not working. I would replace the air mix servo motor in the diagram I sent above.

Both heater hoses are hot coming out of the car's firewall correct?

How exactly did pep boys "diagnose" it? I am always suspicious of diagnoses coming from parts sales people. Most of them do not know a whole lot about cars, just enough to identify and sell parts and sound like they know what they are doing.

Again, I ask, what temperature does the engine reach? And have you touched the heater core hoses to see if they are both warm when the engine is warmed up and the heat switched on?

I am not sure how to check that, but I went to Toyota yesterday for a diagnostic and they said the evaporator case internal door is broken. They said some may have got into it through the vents and cause it to be stuck open.

Hmm, well I guess that is that then. As far as how to check the engine temperature, your car should have a temperature gauge. As long as it is getting somewhere near the middle it should be fine. But if it does not get near there, then your car will not have heat, and probably needs a new thermostat.

And for checking the heater core hoses, if you open the hood and look at the firewall (the wall between the engine and the passenger cabin) you will see two hoses right next to each other going into the firewall. The outer diameter of them is probably approximately an inch. If one of those hoses gets warm, but not the other, then it means that the core is clogged and you would need to flush it out. If neither is warm, it could indicate that you need a thermostat, or some other issue is going on. If they are both warm, then that points to a problem elsewhere in the heat/AC system.

That is the basic path that I was trying to go down. Let us know if there is anything else we can do for you.

The coolant level is good. The car does not overheat and will come up to temperature . If you start it up and let it warm up it will blow hot air . The cooling only happens when you drive it for a while.

Good morning,

Make sure the coolant level is correct.

This could be a clogged heater core. It would need to be flushed out to get rid of the debris so you have heat at idle.

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

A water pump could also cause this issue. The impeller could be the issue.

https://www.2carpros.com/articles/water-pump-replacement

Roy

Heater turns out cold air when I stop on inclines.

Make sure the coolant level is full. Make sure the engine is operating at a normal operating temp. Check to make sure the blend door is working properly.

this guide can help

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

Please run down this guide and report back.

when turn the heater fan on little or no heat come through the vents what is the cause?

It sounds like you have a temperature blend door actuator that is not working, bad engine thermostat or the engine is low on coolant, here is a video and guide to help you find the problem.

https://youtu.be/SNRb6pSwYuU

and

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

Please run down these guides and report back.

With the engine at full operating temperature, locate the two heater hoses where they go into the firewall and feel them to see if they are both hot to the touch. If they are both hot, the heat in that vehicle is controlled by a blend door that regulates heated air flow. it is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.

one of the heater hoses are hot to the touch and one is not i can hold one of the hoses with no problem but the other one i can't it's to hot i did replace the thermostat and after i replace the thermostat and fill the radiator with antifreeze when i crank the engine it will start and cut right back of why the engine want run do the thermostat have something to do with the engine want run what all could be the problem why it want run please help me?

Could be a clogged heater core,try reverse flushing through the heater hoses

i recheck the heater hoses both are hot where are the electric moter/actuator and door located can you send me pictures?

My 2007 Camry will not blow hot air while idling. the thermostat is fine, the coolant level is where it should be, fuses are all good, blower is working. the car does put out heat while driving, but turns cold while at a stop light or stop sign. also if it is sitting in the drive it will be cool air, but if i so much as press on the gas pedal it immediately turns hot for a moment then back to cool. any thoughts?

Hello,

It sounds like you have a clogged heater core or an air pocket stuck in the core check out this guide that tells you how to fix the heater.

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

Also it could be the temperature blend door actuator is not working right here isa guide that will walk you though the repair with diagrams below to show you how the job is done.

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

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

Cheers

Thanks you this post it was the air mix door on the drivers side was the problem on my car cost me $89.00 for the part.

My heater stopped working I checked the coolant level it is full whats wrong can you help me?

Sounds like the temperature blend door actuator (air mix servo) stopped working but to be sure this guide can help us with the actuator location in the diagrams below.

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

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

I have the heater controls which are all electronic to set the temperature at a constant level. Even when turned on 'HOT' I get nothing but normal air or cold air

this is automatic temp control and the only way to properly diagnose this is to have a local pro put his scanner on it to see If there are codes. which means a sensor can be bad inside or outside car causing this. If you follow the chart on the lh side it may give codes to which we can get back with your on what to check. you can also try pulling the ecu-b fuse inside car to see if that resets actuators to get heat. and then check fuse and relay in pic under hood.

I read your previous answers for a similar problem. I conducted the testing that was recommended and came up codes 21,31 and 41. Is there a place I can go to find the codes so I can make the repairs.

Attached are the codes and fault.Forget about code 21 first. It is for the solar sensor and would show up if you are working under the shade.

Only one hose is hot on the heater. There is no sign of a leak but still blow cold on hot temperature.

Good evening.

It sounds like it has a clogged heater core.

What I would try is to remove the hoses from the core and then use a garden hose and run the water through the core. Run it both ways until you get a good clean flow from both sides.

If it comes out good, then hook them back up and try it. If it works, you are good.

If it does not, then the heater core will have to be replaced.

Roy

Hi and thanks for using 2CarPros.com.

If only one of the hoses is hot, then coolant is not flowing through the core. What I suggest is to disconnect both heater core hoses and try to flush water through it to clean dirt and debris that may be blocking it.

Also, here is a link that shows the most common causes of no heat. Look through it to see if it is helpful.

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

Let me know if you have other questions or if this helps.

Take care,
Joe

It works although both line is hot it does not blow hot. The temperature on the hoses range to 180 in 130 out should it be hotter or something else is the cause such as the blend door actuator?

Hi, since both hoses are getting hot as you indicated, then there is flow through the heater core. Based on that, you are most likely correct. You referred to the blend air door. Toyota calls them an air mix control servo motor. That is the next thing that should be checked for operation.

I have attached two pictures for you to look at. The first shows all components under the dash. The second shows where the servo motor is mounted on the HVAC/heater box.

Let us know if this helps.

Take care,
Joe

Temperature controls work fine. The control for the vents works foin, except I cannot get any air to come through the floor vents. If I select one of these modes, I get no air from the lower vents, and it is much noiser, as if the air is restricted. I have read posts indicating this could be a vacuum line issue. Would this be in the dashboard, or under the hood? Where should I look?

Thanks in advance!

If you get a response out of other vent positions ( face, defrost) then the source vacuum is probably ok. Sounds like a actuator door problem under the dash. Might want to look under there to see what moves when you select different vents, could help pin point the problem door.

This guide can help us find the problem.

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

Please run down this guide and report back.

i have a 2002 camry. when the car is in motion the heater works just fine, but if i stop at a stop light or park the heater starts to blow cool air. i added coolant in the radiator and the color of the coolant looks fine. the resovoir is full but for some reason i can't get any heat at idle. i took it to the repair shop and they didn't have a clue. someone help me please

Heater Core — Plugged

WARNING: The heater core inlet hose will become too hot to handle if the system is working correctly.

Check to see that the engine coolant is at the correct level.
Start the engine and turn on the heater.
When the engine coolant reaches operating temperature, feel the heater core inlet and outlet hose to see if they are hot.
If the inlet hose is not hot:

the thermostat is not working correctly.
If the outlet hose is not hot:

the heater core may have an air pocket.
the heater core may be restricted or plugged.
If both are hot, the temperature blend door in the heater plenum may be broken or stuck...
On some occassions, the water pump may have impellers that have disolved, creating your symtoms exactly.

Heater coil is getting hot, but air from vents is staying cool. Air is apparently not being circulated over the heater coil for some reason. All other climate control functions appear to be working fine. The problem would seem to either be a bad climate control module or else something broken or jammed in the system which is preventing the air from circulating through the heater coil. I am getting a little bit of warm air on the driver's side, most of which comes through the driver's side upper vent when the air is being directed through the upper vents. Air from all other vents is cool.

Since heater core is hot suspect and check blend door operation.

Yes, that is what I would think to check next, but how do I check it? Where is the blend door located? how do I access it to check it? and is it something that can be repaired without replacing the whole system? Thanks.