Heater not working properly

JOHNS123

MEMBER
2006 TOYOTA HIGHLANDER
6 CYL
4WD
AUTOMATIC
158,000 MILES

At first the heater would not put out hot air, then it would not stop putting out hot air regardless of where the temperature was set. I looked online and found where the wires from the temperature control tend to break. I looked and they were broken. I soldered new wires on the control and I think it works properly because when I turn it to cold, the engine will stop and when it is turned to hot, the engine starts. This is a hybrid. The problem now is that when I am driving, heat comes out of the vents no matter where the controls are set. When I stop at a light, the air from the vents cools off. I think the blend door on the heater is stuck or not working. Do I have to purchase a new control panel or how can I get to the blend door and check for operation?

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Thursday, April 18th, 2019 AT 8:00 AM

13 Replies

KEN L

MASTER CERTIFIED MECHANIC
42,878 POSTS

Hello,

It sounds like you got the wiring connected incorrectly. here is a guide to help you test the connections and the HVAC wiring diagrams so you can see how the system works:

https://www.2carpros.com/articles/how-to-check-wiring

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

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Friday, April 19th, 2019 AT 12:42 PM

JOHNS123

MEMBER
3 POSTS

So it is still not fixed. I looked over the wiring diagrams and thought about the problem and decided that it could be one of the servo motors not working. I then took the easy route and asked the local Toyota dealer to look at it. They said that in their opinion, I damaged the circuit board when I re-soldered the wires on the temperature control. They wanted $1,200.00 for a new controller. Thinking they knew more than I did, I ordered a controller and put it in. Didn't fix it. I went back to my original thought of a bad servo motor likely on the blend door. I found it and after removing it, it tested bad. I have a new one coming so I will update you when I get it in.

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Friday, April 26th, 2019 AT 9:46 AM

KEN L

MASTER CERTIFIED MECHANIC
42,878 POSTS

Good work, please let me know what happens, 9 times out of 10 it is the blend door actuators. Here is a guide to help walk you through the repair with diagrams below to show you on your car:

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

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

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Saturday, April 27th, 2019 AT 11:14 AM

JOHNS123

MEMBER
3 POSTS

Thank you for your help. I had two issues that are now resolved. There were wires broken on the control panel controlling the temperature and the blend door servo motor was not working. I replaced both items and now can control the heat settings. I did take the servo motor apart to see what had happened. There was a black coating on the armature that resembles carbon. I cleaned it off and the motor works now but of course I had to cut the motor apart so it isn't usable. Thank you again for your help, I learned a lot on this one.

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Wednesday, May 1st, 2019 AT 7:33 AM

KEN L

MASTER CERTIFIED MECHANIC
42,878 POSTS

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

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Wednesday, May 1st, 2019 AT 12:28 PM

RYENGO

MEMBER
1 POST
2009 TOYOTA HIGHLANDER
V6
4WD
AUTOMATIC
95,000 MILES

Car was diagnosed to have a heating problem. The A/C works. Can only produce cool and not heat. The Toyota says that it will cost $4000 to repair and I want to know from your experience if there is a cheaper way to do this.
What alternate reliable source or type of portable heater or car heater do you recommend that is cheaper and effective to use. I looked on Amazon and they have portable or battery connected heaters to use but I do not know if they do work. Please help me. I do not have $4000 to spend.
Usually for most cars that I know, the A/c goes bad but the heater still works. This case is strange.

Thank you for listening and I hope to hear from you

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Wednesday, May 1st, 2019 AT 12:28 PM (Merged)

MHPAUTOS

MECHANIC
31,938 POSTS

There are two main problems that may be going on here, a blocked heater core, this is easily checked with the engine at normal temp, both heater hoses should be hot to touch, if both are hot, the blend door system has failed in the cool position, not allowing hot air to circulate, after market heaters I have never sen or had any information, I doubt that anything can be adapted to suit the car.

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Wednesday, May 1st, 2019 AT 12:28 PM (Merged)

2CP-ARCHIVES

MEMBER
4,542 POSTS
2005 TOYOTA HIGHLANDER
125 MILES

Happy Thanksgiving! My Toyota Highlander 2005 has a more than normal amount of smoke coming out of the exhaust pipe coupled with a knocking noise (that goes from louder to softer) upon starting the car. The smoke does not go away. There is a strong gasoline smell also. What is happening? I'm afraid to drive it. I'm a single mother and low on funds so I'm hoping this is not going to be an expensive fix!

Also the heater is not working in the car, only the A/C.

Thanks for your help!

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Wednesday, May 1st, 2019 AT 12:28 PM (Merged)

KHLOW2008

MECHANIC
41,815 POSTS

Check the engine oil level and top up if necessarily.
Ensure coolant level is correct. You need to check at radiator end when engine is cold.
Based on symptoms, this might not be a cheap fix.

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Wednesday, May 1st, 2019 AT 12:28 PM (Merged)

2CP-ARCHIVES

MEMBER
4,542 POSTS
2004 TOYOTA HIGHLANDER

I started having a problem with the heat working. I could hear the air coming out but it was cold. I pulled the button off and noticed the bolt was lose so I tightened it and it worked fine. As time went on I had to tighten it more often and then eventually I had to tighten it and apply pressure. Being broke I wedged a penny on the side of the dial (to permenantly apply pressure) and it worked (sometimes). Now when I turn the heat on nothing happens unless it is as high as it can go and it gives a VERY loud rrrrr noise. Like the fan is running high speed but I get little or no heat not to mention how annoying the sound is. Winter is here and I have three children and have to have heat. What do I do?

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Wednesday, May 1st, 2019 AT 12:29 PM (Merged)

ASEMASTER6371

MECHANIC
52,797 POSTS

First, the blower motor is the noise.

Second, you will have to replace the control for the heat that you have been messing with. No more band aids. It needs to be fixed right

Roy

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Wednesday, May 1st, 2019 AT 12:29 PM (Merged)

ROBIBARRAJ

MEMBER
1 POST
2003 TOYOTA HIGHLANDER
2.3L
4 CYL
2WD
AUTOMATIC
70,000 MILES

Heater turned on to defrost, temp to max heat, fan on high, does not get warm.

Heater turned on to defrost, temp to max heat, fan on mid setting, starts getting warm.

Heater intermittently warming based on settings in the fan speed, and temp control switch, also not getting hot enough.

Please help!

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Wednesday, May 1st, 2019 AT 12:29 PM (Merged)

HMAC300

MECHANIC
48,601 POSTS

Try pulling heater fuse inside vehicle it may reset air mix motor if that doesn't work have it scanned for codes make sure both heater hoses are hot check coolant level as well

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Wednesday, May 1st, 2019 AT 12:29 PM (Merged)