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Air mix problems with heater

65K views 19 replies 8 participants last post by  concrete7  
#1 ·
Hi guys,

Been searching the forums here and found some good info on a problem I have but I needed some more clarification.

Ok the problem.

Today I got in my truck and turned on the heater. The engine had warmed up nicely but I am not getting any hot air out of the vents.

When I turn the temperature control to cold the air does get colder.

I have also noticed that its doing a very poor job of de-misting the cab.

Its a 2008 Ext Cab 4wd 4cyl tacoma

The first thing I just wanted to double check was the fuse for the air mix servo. Where is this located?

Then, if its not that, what else should I start checking?

All the best,

Stuart
 
#2 ·
to add more info

update on my investigations.

Just been out having a proper look round the truck. I've noticed that some slightly warm air is coming out of the passenger side vent and passenger side floor vent. All the other vents including wind shield de-mister are still blowing cold.

The passenger side vents do respond to the temperature control. Though as I said, even when on MAX heat the air still only comes out slightly warm.

The recirculate button works as does the AC button.

Any information would be really appreciated
 
#3 ·
Another update and hopefully someone can help with this part.

I've identified the Air Mix Servo as being the problem.

I can hear it moving when going from max cold to about 75% cold / 25% warm then it sounds like it jams and so is not moving the flaps to fully warm.

Now..... how do I remove this servo so I can check for blockage?
 
#4 ·
I had a promblem with my 07 from day one not getting much heat from vents
took it back I was told their is foam glued inside the vents to keep air warm and the glue was bad and the foam blocks heat from coming through they said they had few with this problem good as new now after they fixed it
FLYGUY
 
#5 ·
Ok thought I better update this thread to say I fixed the heater problem.

After a lot of fault finding work I whittled it down to being a problem with the Air Mix Servo gears. They were turning the heater cam about half way then jammed.

I removed the Air Mix Servo and opened it up and found that the plastic retaining lip and broken off.



This meant the centre pin of the black gear would slip out of alignment when the whole servo met resistance of the heater cam and would stop the servo from working



My fix was to put a very small screw through the top lid of the servo to create a lip so that the pin could not slip out the side again.

This seems to have solved the problem
 
#17 ·
Paying Toyota to trouble shoot this same Problem

My 2007 Tacoma is having the same sort of problems, let me explain, as of late when i start my truck and it reaches operating temp, i crank up the fan speed and no air or heat seems to come from anywhere, it makes a whistling noise, like it is exiting out releif holes somewhere. Now this is where it gets strange, I then switch the temp control from Hot to Cold and the air returns to full force in the cold position and I can direct it to defrost, floor, blend (defrost and floor) dash vents, everthing works as it should. However as I start to rotate the tempature dial past midway I hear a faint "click" and I loose the air force and temp is cold. Now sometimes when I repeat this proceedure with the temp control dial I get lucky and it works fine for a while, but as I drive I hear a loud "Thump" which sounds like a airbox door closing and imediately loose my air force and heat.
I took it into the Charesglen Toyota dealer in Calgary and explained it to them they and trouble shooted the problem to be my heater control assembly and here is what the work order said
"Removed heater control assembly, checked voltage and resistance of terminals for Hot/Cold Dial, Max/Low Dial and Ventilation Dial. Found Inaccurate readings recomend replacment of assembly"
The part in question is $857.29 plus 0.5 labour.
However my question is will you not get a voltage drop when power is sent to the Air Mix Servo gears?

From all the great info you guys have provided here in this forum I am wondering, could all this be the Air Mix Servo gears problem too.
I ordered a used heater control module (thee dials and 2 buttons) for $75.00 and will replace it with mine when it arrives, as I have my doubts the tech troubleshooted this problem correctly for the $150.00 they charged.

What say ye?... I would like your valued opinion if you would be so kind.

Thanks -you very much!!!!!



Ok thought I better update this thread to say I fixed the heater problem.

After a lot of fault finding work I whittled it down to being a problem with the Air Mix Servo gears. They were turning the heater cam about half way then jammed.

I removed the Air Mix Servo and opened it up and found that the plastic retaining lip and broken off.



This meant the centre pin of the black gear would slip out of alignment when the whole servo met resistance of the heater cam and would stop the servo from working



My fix was to put a very small screw through the top lid of the servo to create a lip so that the pin could not slip out the side again.

This seems to have solved the problem
 
#7 ·
Cheers!

Actually I was lucky. I was just about able to remove the footwell duct on the passenger side that allowed me to get easy access to remove the Air Mix Servo
 
#10 ·
Hey dude,

So sorry for not getting back to you.

Just for the record, the Air Mix Servo is located in the passenger side footwell. Its on the left of the footwell, behind the footwell heating vent. This is what makes it difficult to get at. If you can lever that off you can get at it.
 
#12 ·
blender door foam

The TSB to repair the blender door foam that becomes unglued and plugs the heater core is a common problem on the early models tacomas. Warranty pays 4.7 hrs labour, plus refrigerant as required. My tacoma has just come up with the same problem, too many miles for warranty, dealer says its at least 8 hours labour, plus shop supplies and extras such as refrigerant. Has anyone attempted to do this themselves and what was it like ?. I know that the whole dash has to come out to get at it, its not a fun job. I am getting ready to attempt the repair myself, any help would be appreciated, thanks Curt
 
#13 ·
Heater blend door foam problem

Hi everyone, I know there is al lot of discussion on this subject, but has anyone acually done the repair themselves. The TSB warranty pays 4.7 hrs. but since my tacoma has too many miles the dealer tells me its at least a 8 hr. job plus shop supplies, parts ect. Sounds like about $1300.00 worth total or more. I am getting ready to attempt the repair myself, I know the entire dash has to come out to get at the heater box, then ac. core and heater core has to be removed as well. It seems that the foam on the blender door comes off and plugs the air flow through the heater core. Any help or advice would be greatly appreciated. Thanks Curt
 
#14 ·
Curt,

Good luck! Let us know how your repair goes.

This is way past my skill level for this one, and I want to get it done in time for the winter. It took my dealer in SoCal about 3-4 days to order the part for the TSB (they got it last week), and was quoted $850-900 for parts + labor (they quoted 9hrs), because it's such a PITA. I do have an aftermarket extended warranty which will hopefully defer the cost on my '07, but it's still a whopper of a bill.

I will take it in tomorrow, hopefully they will turn it around by Friday for me.
 
#15 ·
got it fixed

Took it to the dealer last week and got it fixed. It was a 2 day job, they basically had to pull the whole dash off, from what I heard.

Fortunately my aftermarket extended warranty covered it, so what was quoted as a $900 job came out to a mere $100 deductible out of my pocket.

Nice to have warm heat blowing strong again, esp. now that winter is almost here.
 
#16 ·
Was yours the air door foam problem, or the air mix servo?

Thanks, just want to clarify
 
#18 ·
2007 Tacoma Heater problem...HELP!!!!

My 2007 Tacoma is having the same sort of problems, let me explain, as of late when i start my truck and it reaches operating temp, i crank up the fan speed and no air or heat seems to come from anywhere, it makes a whistling noise, like it is exiting out releif holes somewhere. Now this is where it gets strange, I then switch the temp control from Hot to Cold and the air returns to full force in the cold position and I can direct it to defrost, floor, blend (defrost and floor) dash vents, everthing works as it should. However as I start to rotate the tempature dial past midway I hear a faint "click" and I loose the air force and temp is cold. Now sometimes when I repeat this proceedure with the temp control dial I get lucky and it works fine for a while, but as I drive I hear a loud "Thump" which sounds like a airbox door closing and imediately loose my air force and heat.
I took it into the Charesglen Toyota dealer in Calgary and explained it to them they and trouble shooted the problem to be my heater control assembly and here is what the work order said
"Removed heater control assembly, checked voltage and resistance of terminals for Hot/Cold Dial, Max/Low Dial and Ventilation Dial. Found Inaccurate readings recomend replacment of assembly"
The part in question is $857.29 plus 0.5 labour.
However my question is will you not get a voltage drop when power is sent to the Air Mix Servo gears?

From all the great info you guys have provided here in this forum I am wondering, could all this be the Air Mix Servo gears problem too.
I ordered a used heater control module (thee dials and 2 buttons) for $75.00 and will replace it with mine when it arrives, as I have my doubts the tech troubleshooted this problem correctly for the $150.00 they charged.

What say ye?... I would like your valued opinion if you would be so kind.

Thanks -you very much!!!!!
 
#19 ·
Your approach is what I would consider for the symptoms you suggest. The FSM requires a meter and a battery power supply to test these.
 
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#20 ·
Heater blend door foam

O.K. I put the truck in the shop and decided to get to the root of the problem. It was just as described in toyotas tsb. #0072-09 . The glue on the blender door that holds the sealing foam on lets go, and the foam then lays across the heater core, preventing any air from passing through, thus only cold air through system. The tsb requires the removale of the entire system, about a 8 hour job for someone with experience. I removed my entire dash and was about to continue, which requires the removale of the heater lines and ac lines(requiring a recharge) and dropping the steering column along with a lot more stuff to take out just to pull the entire ac-heater unit out. Well I was able to take a 1/4 inch impact rachet and remove the lower screws on the heater box. Twisted that out of the way,removed the bracket that positions the heater core tubes and was able to drop and angle the heater core. Lone behold there is the foam that has come unglued, blocking the air flow to the heater core. I reached up and pulled it all off, one end was still holding on. After removing it, I realized that the blender door closes fairly tight even without the foam. I put it all back together and it works just fine. If I had to do it again it would still take me about 3-4 hours, better than the $1600.00 the dealer quoted me. Curt