Defrost problem.

[BlackWorksInc]

I just wanted to update this thread with this picture I took earlier in the week. This is a 2014 Toyota Sienna I was replacing the HVAC box on, I took a picture because it perfectly illustrates what I was talking about.

 

[nevada]

BlackWorksInc:
Your explanations couldn't be more clear and regarding engineering design, I further agree that much makes little sense here. I regard this vehicle to be over-engineered to a degree equalled only by the late Saabs and too many Volvos. Technology is great, when it works right.
I would have just liked to be able to keep the fog down and my feet warm without having to blast air, set around 80 degrees, in my face until my sinus cavity achieves Sahara dryness while my feet remain annoyingly chilled.
It is what it is.

enumify:
Planning to change cabin air filter anyway, never linked it as possible cause, it's just due.

Thanks for the patient input from all.

ive read a lot on this, but not recently, so forgive me if its already been said,

are you keeping it set to FRESH AIR?
recirculate will make the windows fog up fast.

 

[Fred Ritchie]

I've tried more combinations of settings (ie:fresh air on/off, AC on/off, etc etc) than I can remember and problem persisted.
Did get response from Toyota USA, unfortunately not a tech but I can't imagine anyone being more clear than BlackWorksInc, thanks again.
I'm thinking this is going to be seasonal problem in this area. Fall and Spring can be uncommonly humid while still being chilly enough to require a bit of heat. It's now cold enough that there is virtually no humidity and the system can cope and it does seem to be properly working mechanically.
Can't say I'm happy with the situation but if it ain't broke I can't fix it.

 

[chitown40]

Is your A/C system fully charged? The defrost meechanism, especially with reduced airflow caused by splitting between floor vents and dash vents requires the A/C to help dry the air which is what is causing your windshield to remain fogged.

Also, is the intakes between the windshield and hood clear of debris, leaves, etc? Airflow requires intake air or else it will create negative pressure -- same reason to ensure your cabin air filter is clear.

You can check the sight glass in the engine compartment to see if it's clear or cloudy with the A/C compressor running to determine any issue with the A/C system.

 

[earthrealm]

[MENTION=66389]BlackWorksInc[/MENTION], i have a similar problem.
i recently had my dash torn apart to replace a leaking evaporator. now the ac air vent directional controls dont work anymore, air constantly blows on my feet/floor...and then the front vents, front windshield defrost doesnt work, no air comes out from the defrost vents, the buttons light up on the hvac panel, but air flow direction is not responding to the buttons.

i am asking if its a simple fix, so i can tinker on it myself, and not go back to the place where the dash was worked on

 

[BlackWorksInc]

[MENTION=66389]BlackWorksInc[/MENTION], i have a similar problem.
i recently had my dash torn apart to replace a leaking evaporator. now the ac air vent directional controls dont work anymore, air constantly blows on my feet/floor...and then the front vents, front windshield defrost doesnt work, no air comes out from the defrost vents, the buttons light up on the hvac panel, but air flow direction is not responding to the buttons.

i am asking if its a simple fix, so i can tinker on it myself, and not go back to the place where the dash was worked on

I'd take it back to the shop that did the evaporator and have them look at it on their time. Something wasn't connected properly or something else, but that's why they have warranty on their work.

 

[earthrealm]

I'd take it back to the shop that did the evaporator and have them look at it on their time. Something wasn't connected properly or something else, but that's why they have warranty on their work.

so i took it back to them, got a call about an hour later that the problem was fixed, went and collected the car..yeah everything was fixed and working as it should.

was driving today and noticed that funky smells was entering the car, even with the recirc button light on, i removed the glove box and observ ed.

the recirc button seeems to be working opposite to default, that is with the recirc button light off, the fresh air inlet door closes tightly-and cannot be easily opened by hand...but when the recirc button light is lit, the door is not tight, and can be opened easily by hand.

i really would not want to go back to the repair place again ##%&@@, do you have a clue what i can do to reverse this?

 

[AuSeeker]

I'm not sure that the recirculating air servo electrical connector can be connected wrong but maybe possible, but I'm thinking the servo arm maybe not engaging the door properly, i.e. not in the slot.

 

[BlackWorksInc]

so i took it back to them, got a call about an hour later that the problem was fixed, went and collected the car..yeah everything was fixed and working as it should.

was driving today and noticed that funky smells was entering the car, even with the recirc button light on, i removed the glove box and observ ed.

the recirc button seeems to be working opposite to default, that is with the recirc button light off, the fresh air inlet door closes tightly-and cannot be easily opened by hand...but when the recirc button light is lit, the door is not tight, and can be opened easily by hand.

i really would not want to go back to the repair place again ##%&@@, do you have a clue what i can do to reverse this?

That's weird... I don't know if you can actually swap the connector and/or have it set up in reverse...

The only thing I can think of is that the motor/actuator isn't timed correctly. I can't seem to get my pictures from photobucket from all my older threads and I'm not payning those sharks...

But if you can get the actuator off you can run it in your hand and then carefully re-time the door (just be careful not to force the door too much.)

 

[earthrealm]

ok, thn ks, would hunt for threads with pics on how to get the actuator off, photobucket has taken off all the pics on your thread where you posted steps on the removal

 

[earthrealm]

That's weird... I don't know if you can actually swap the connector and/or have it set up in reverse...

The only thing I can think of is that the motor/actuator isn't timed correctly. I can't seem to get my pictures from photobucket from all my older threads and I'm not payning those sharks...

But if you can get the actuator off you can run it in your hand and then carefully re-time the door (just be careful not to force the door too much.)

aha, so i have found the problem!.
the servo arm jumped out of its track . similar thing has happened to me in the past and i was able to push the arm back, now i am trying and its impossible,

attached are the pictures, in the schematic you attached earlier, is it possible to remove the complete airbox i circled in blue, without tearing the dash apart?
the major difficulty is not having enough room to push back the arm.

i also attached the pic of the arm and the track.

 

[BlackWorksInc]

[MENTION=78511]earthrealm[/MENTION] What I would try to do is get the actuator off the box and then see if you can GENTLY pull the arm back over the slot in the air door lever. If you can't you might be able to loosen that gold screw after you have the actuator off to get some wiggle room to do so.

Usually you can't get the blower housing assembly off the main HVAC box without it on a bench because of clips and screws on the backside. I don't remember how it is for a 4th gen, but most of the other Toyota's I have done have been this way.

 

[earthrealm]

[MENTION=78511]earthrealm[/MENTION] What I would try to do is get the actuator off the box and then see if you can GENTLY pull the arm back over the slot in the air door lever. If you can't you might be able to loosen that gold screw after you have the actuator off to get some wiggle room to do so.

Usually you can't get the blower housing assembly off the main HVAC box without it on a bench because of clips and screws on the backside. I don't remember how it is for a 4th gen, but most of the other Toyota's I have done have been this way.

i didnt have to do all that, had a clue, and decided to use a longer studier rod to pry the actuator arm while using my fingers to turn the tracks from the inside, it worked perfectly, and while testing the arm went off the tracks again.

so i discovered it appears to be a design mechanism to prevent the motor from burning out or breaking the arm, once it meets any resistance on the tracks, it will jump off track.
below is the simple tool i used..lol

also because i left the cables unplugged throughout the night, when i started the truck this morning, the check engine ,vsc, trac and other lights came on..i was thinking i would need to do a ZPC, but all the lights went off, on my 4th start-drive cycle

 

[AuSeeker]

i didnt have to do all that, had a clue, and decided to use a longer studier rod to pry the actuator arm while using my fingers to turn the tracks from the inside, it worked perfectly, and while testing the arm went off the tracks again.

so i discovered it appears to be a design mechanism to prevent the motor from burning out or breaking the arm, once it meets any resistance on the tracks, it will jump off track.
below is the simple tool i used..lol

also because i left the cables unplugged throughout the night, when i started the truck this morning, the check engine ,vsc, trac and other lights came on..i was thinking i would need to do a ZPC, but all the lights went off, on my 4th start-drive cycle

So are you saying that it's still not working?

What is causing the resistance that's making it jump off?

 

[BlackWorksInc]

i didnt have to do all that, had a clue, and decided to use a longer studier rod to pry the actuator arm while using my fingers to turn the tracks from the inside, it worked perfectly, and while testing the arm went off the tracks again.

so i discovered it appears to be a design mechanism to prevent the motor from burning out or breaking the arm, once it meets any resistance on the tracks, it will jump off track.
below is the simple tool i used..lol

also because i left the cables unplugged throughout the night, when i started the truck this morning, the check engine ,vsc, trac and other lights came on..i was thinking i would need to do a ZPC, but all the lights went off, on my 4th start-drive cycle

Sounds like the actuator is out of time then. I would just unscrew the actuator and have it move from one setting to the other, then reinstall it in that setting (i.e. turn the recirculation on, let the actuator settle to it's intended setting, install actuator in recirculation mode).

I've had to do that once or twice on other vehicles.

 

[earthrealm]

So are you saying that it's still not working?

What is causing the resistance that's making it jump off?

My hand was in the way..preventing the door from opening..that was the resistance that made it go off track again.
But since i had my study tool..it was a simple fix again.
Everything is working ok now..airflow has increased back to normal and i can use my usual airflow #1 or #2..unlike then twas only airflow #3 that was able to push out a decent amount of air.
Also no more exhaust fumes enter the cabin.
[MENTION=66389]BlackWorksInc[/MENTION]...thnks for the tips.didnt hv to do all that.everything is ok now

 

[AusTex4x4Sport]

I'd take it back to the shop that did the evaporator and have them look at it on their time. Something wasn't connected properly or something else, but that's why they have warranty on their work.

Similar problem. Had the evap core and heater core replaced at beginning of summer and all "seemed" to work well until this morning when for the first time I needed to defog the front window. All the control lights work and I have air blowing from the side vents toward the windows, but I have zero flow on the windshield. The diagram shows a distribution box for defrost that suggests windshield and side vents both flow from that box. How could there be flow to the side vents and not the windshield, or is maybe the side vent flow just the normal HVAC system and not necessarily from the defrost system? I'll take it back to the shop that did the cores, but I'd like to hear your opinion beforehand. This has to be fixed soon; I was "blind" this morning because I drive due east to get to work and couldn't see a thing with the bright sun on my foggy window.

 

[AusTex4x4Sport]

Similar problem. Had the evap core and heater core replaced at beginning of summer and all "seemed" to work well until this morning when for the first time I needed to defog the front window. All the control lights work and I have air blowing from the side vents toward the windows, but I have zero flow on the windshield. The diagram shows a distribution box for defrost that suggests windshield and side vents both flow from that box. How could there be flow to the side vents and not the windshield, or is maybe the side vent flow just the normal HVAC system and not necessarily from the defrost system? I'll take it back to the shop that did the cores, but I'd like to hear your opinion beforehand. This has to be fixed soon; I was "blind" this morning because I drive due east to get to work and couldn't see a thing with the bright sun on my foggy window.

UPDATE: The side vent flow is only coming from the larger regular system section and not the smaller defrost section on top, so there's no flow through the defrost system at all, in spite of having set the fan on high. Actually, with the fan running on lower auto setting, the fan does notch up two speeds when I push the defrost button, so everything seems to work except the distribution system. With defrost on, I still get full glow from center and side vents (except the small side defrost vents.

There must be a servo not working to redirect the air for defrost. Can anyone describe where that servo is?

Thanks

 

[earthrealm]

same prolem occured again, could not recall what i did the last time.. searched out this thread, and was ale to pry the actuator ack onto its tracks in under 3mins. nice!