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04/27/16 My front floor vents (driver & passenger) in my 5.7 L dbl cab 2007 tundra were not allowing any a/c or heat flow at all to my feet. I live in mtns and need heat to my feet in the winter. No matter which position my mode selector (defrost/face/face & floor etc) was on, there was no air flow at all but all other vents worked appropriately in relation to which position the mode selector was on. The fix....took less than 10 min. Slide seat all the way back to maximize front floor room, locate your heat shoot then I just pulled gently backward (toward firewall) and removed it from a forward facing sleeve (visible if your head rests near gas pedal and you look toward the dash. There is just one nut/bolt holding this 2-holed chute in place but mine was pretty loose so I was very careful to pull it off of its connecting plastic air chute w/o removing bolt, and then used my long finger to push against a plastic wall that slid easily open with slight force. I figure the servo is just broken. So now I will always have some air going to feet (heat or A/C) depending on the mode setting and yet there still seems to be enough air coming to my face when in face mode or any other mode and this works fine with me. Plenty of A/C hitting my face and my feet now. And my wet shoes now dry out after a 2 hour drive through snowy weather. I am very proud of my accomplishment! And I have short fingers. The door is a slider to the L as you look at it from under the dash and very simple, so even a girl like me can do it. It's about 4 inches from the exposed end of the heater duct after you have removed the visible part of the duct (the 2-holed chute)
 

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my 2008 SR5 CM had the same issues (delayed start of the AC and then only blowing out the windshield and defrost vents.) I had a aftermarket stereo installed and one of the wires was caught in the exposed gears. I followed Blackmoses on YouTube to remove the entire assembly, re-sync the gears and then reassemble. Its a bit of a challenge trying to line up all the gears and pins to reassemble but after a entire saturday afternoon I'm glad to say its finally fixed.

I noticed a few others that had similar issues and those with the aftermarket products might want to take a closer look at the gears that are visible and make sure nothing has obstructed them.

Good luck!
 

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Hello all.

2007 Crewmax Limited 4x4 5.7. 242,409 miles.

So I had this issue just last weekend and figured out a fix for my truck at least. The mode door was stuck on defrost, just like all other symptoms. I took as much of the dash apart to see all 5 of the motors. There are 5! of them.
In no particular order:
1 - for recirculate / fresh air just above the blower motor.
2 - Passenger side lower motor on the main box is passenger side temp blend door.
3 - Passenger side upper motor is not real easy to figure, but it operates with the temp blend doors. Either driver or passenger, so I think it closes off the heater core to separate from the evap core. Since there is no water valve to shut off the heater core, I think this helps keep heat from bleeding into the a/c core side.
4 - Driver side lower motor on main box is drivers temp blend door.
5 - Drivers side upper motor is the mode door(s) that we all seem to have issues with.

First I tried to remove the motor, but that doesn't work. After taking the two or three small screws off, the motor will not release from the bracket / gear assembly. Looking at parts diagrams, it appears that gear assembly has to be removed from the box, then I'm sure there are clips to remove the motor shaft from the gears. So that ain't happening without removing the complete dash and support metal brackets....

Next I felt around all the gears I could to find any that are stuck. So there is a small gear that is hidden behind ductwork that runs under the drivers seat for rear seat heat. I pulled the carpet from the drivers side and that duct to get access. This gear was VERY tight. Good news is it can be removed easily and then the system works. I will post some pictures to help see what I mean.

The gear in question moves a blend door for the rear vents from floor to "dash" (back of center console). The door moves easily, but the gear is very tight. Either the door isn't moving all the way open / closed and is sticking, or the whole assembly has warped / shrunk or otherwise changed the clearances in the gears, thus causing a binding situation. The motor is probably wore out from 11ish years of use, but it works fine without that gear...

To finish up, I put the rear mode to blow from the center console vents and left the gear out completely. It won't change in winter to rear floor vents, but who cares as long as the front system works.

I'm in Tucson and its getting hot. The A/C blowing out the defrost vent is useless...
 

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Dash torn apart, Look at white gears in center of picture. Carpet has to be pulled back to get floor duct out of the way to access these gears.



Closer view of gears in question. Remove the middle one if it seems very tight. It has two missing teeth which are used to align it between the door gear and the other gear. To install it with the door aligned was very difficult. Either the door isn't closing all the way, or something else is wrong, but without that gear, the mode works correctly for the front vents...



Driver side motors. (top is problem one)



Passenger side motors. (no issues with these)
 

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Wow @Pretaco, you deserve a medal - both for your attempt and the documentation.

I paid the $1600 to the dealer a few years back to get it fixed - and while that problem hasn't returned, just this winter, a new one has...

When I set the climate control to LO it's freezing cold. When I set it up one notch (65) it's warm, and 66 or higher it's HOT.

I talked to the dealer, and they said that it'd be at least $900 for just the part, and about as much in labor to get the dash ripped out and fixed. At 11 years old, I think I'm gonna live with it. Of course, if you think this is fixable via the approach you used, I may have to start to tinker.
 

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Wow @Pretaco, you deserve a medal - both for your attempt and the documentation.

I paid the $1600 to the dealer a few years back to get it fixed - and while that problem hasn't returned, just this winter, a new one has...

When I set the climate control to LO it's freezing cold. When I set it up one notch (65) it's warm, and 66 or higher it's HOT.

I talked to the dealer, and they said that it'd be at least $900 for just the part, and about as much in labor to get the dash ripped out and fixed. At 11 years old, I think I'm gonna live with it. Of course, if you think this is fixable via the approach you used, I may have to start to tinker.
That problem would be something with the temp blend door, or the controller. Does it do the same thing on auto climate and on manual? To go from very cold to very hot, the blend doors are moving all the way around, so the problem isn't that they stick, but maybe the internal position sensor is bad on the motor, so it just keeps going since the controller doesn't know where the motor is (so it doesn't know when to stop the motor).

Start with a visual inspection of the wiring from motors to the dash harness to be sure none of them have been pinched or disconnected. The two motors on the bottom of the box (one on each side) are the temperature blend doors, so those are where to look.
 

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I just recently had this issue. Today I was able to successfully fully repair the issue and all functionality is restored. It is a total pain in the arse, took about 12 hours. Thankfully I have 60/40 split bench.

1. Remove lower cover in the center hump (two plastic screws each side)
2. Remove drivers kick plate (one plastic screw at the carpet meeting point)
3. Remove drivers sillplate (pull up)
3. Remove lower dash panel (two bolts either side in the lower corners)
4. Pull the lower dash from the mounting (disconnect all wiring)
5. Remove the knee airbag assembly (four bolts and a wire harness) harness has a black clip that must be pried gently upward to remove the plug.
6. Remove the OBD II port from the lower dash panel
7. Remove parking brake from lower dash panel
8. Remove light from lower dash panel and set panel aside
9. Remove drivers foot duct (one bolt under where the airbag was attached to the brake assembly bracket) now gently pull the duct from the heating unit
10. Remove the gas pedal (two nuts and one wire harness) set aside
11. Remove cubby hole in the center dash (pull outward)
12. Pull the carpet back (two pieces of velcro at the top (be careful here you can easily pull the staples out the velcro)
13. Remove the exposed structural brace bolt (bottom of brace) this is the brace next to the heater box
14. Remove the foot heater duct piece that is still attached to the heater (piece where the duct was removed from early) two screws
15. To the hard part, remove the drivers servo assembly (four screws top and bottom center and left and right center)
16. For the screw behind the structural support its easiest to drill a hole in the support to remove it unless you have specialty tools you can get it out. (I removed mine with a micro ratcheting driver and later drilled a hole to reinstall it) Careful when drilling its easy to push right into the servo plate and heater box
17. Remove the servo wiring (also very tedious)
18. Maneuver the servo plate off the heater assembly
19. Once the servo plate is removed inspect for damaged gears and the like (mine was fine and the jamming was likely caused by accessory wires that I found caught up in the gears and caused the gear to become off by a few teeth)
20. On the backside of the servo plate there are two large gears with a gap in there teeth those gapped teeth need to be meshed in order to have everything in sync for reinstallation. Also there is two alignment holes in the servo plate and the upper white gear. (The servos cant be turned by hand use on of the plugs in vehicle to align the servo plate servos) If your lucky these are already in alignment if not it'll take some trial and error (your shooting to have the gapped gear areas meshed together and the alignment holes in the servo plate line up with the white gear holes.
21. Next is the black gear on the servo plate (also has a big tooth) this tooth aligns with triangular gear on the heater (this triangular gear has a hole in it for matching up with the servo plate alignment holes.

This is where is gets ready tedious and lots of curse words were used.

22. There is a diagram for setting the flaps in the proper orientation in the service manual I'll see if I can post if when I'm done, push the upper most linkage (defrost I think?) at the bottom of the linkage clockwise (this should raise the linkage) you want it all the way up and you'll need something to hold it in place (I used a jewelers screwdriver to wedge between the forward shaft and the heater forward wall to hold it into position)
23. The next linkage down needs to be rotated all the way so the small triangular gear at the top move towards the passenger compartment, again line up their big teeth (should have alignment paint on them as well) you may need to push the upper cog (it moves via the servo plate white gear channel so its somewhat independent to the movement with the plate removed) up first in order to do this as sometimes it prevents the linkage from swinging up easily (rotation is counter clockwise).
24. Prepare to reinstall the servo plate onto the heater. (I tired about 30-40 times and only got it once) don't make the mistake I made and run the air conditioning alignment in Techstream it screws up the gear alignment if you have manual A/C controls like I do, I don't know if it works for the auto climate or not.

**Note its much easier to remove the bottom servo from the servo plate and install the black gear onto the heater side (again align the big teeth and slide the black gear onto the resting position (circular hole toward the engine bay in front of the triangular gear).

25. Optional if you are performing the reinstallation with the black gear on the heater side, remove the lower servo (be careful you can easily break the little clip that holds the servo on the white gear.
26. Optional Remove the black gear and place it on the heater side as mentioned above
27. Optional Remove the two screws holding the lower servo to the servo plate
28. Optional pry the clip on the back of the servo plate holding the servo to the white gear and remove the lower servo.
29. Reinstall the servo plate, the lower flapper needs to be all the way down (I just held this as I reistalled but you can use a rubber band to hold it as well) you also need to use a screw driver, punch or drift pin to put through the alignment hole in the servo plate, white gears, the large triangular gear and heater box hole to ensure proper alignment.
30. If you have DC (like me or a CM) there is the gears for the rear vents all the way at the bottom toward the passenger compartment (little round gear and a medium triangular gear. There is no alignment diagram for them and they do not get aligned with there big teeth lined up, mine was aligned somewhere towards the bottom center. (you'll just have to trial and error this, took me about 10 tries) you'll know this is out of alignment when the controls allow movement in one direction and then it binds trying to go back (you'll be stuck in defrost only again).
31. Allot of trail and error but once the plate is on or you think your good remove all the things you used to hold the upper and lower linkage in position if used
32. Optional if you removed the lower servo reinstall it now, you'll need to use the servo plug to turn the servo shaft so the flat portion is straight up and down to install. If the black gear isn't straight up and down make sure it stay meshed with triangular by keeping pressure on the servo plate and rotate by hand or needle nose pliers until it is straight up and down with the flat section for insertion of the servo. Ensure the other servo isn't plugged in or you'll mess up the alignment and have to start over.

**Note the lower servo needs to have the flat piece straight up and down for proper alignment with the black gear if your removing it. Weather or not you remove the lower servo to make the reinstallation easier you likely need to remove it to align the servo plate gearing anyway, use the servo plugs to turn and align the servos and gears dont plug the plug in all the way as you need to quickly remove the plug/s when the gears line up properly (It's also easier to remove the servos align the gears and then individually plug in just a servo to align its shaft for reinsertion into the servo plate.) You likely have a 45-60 second delay until you can control the servos, dont worry this will go away once everything is aligned and installed properly.

33. Install the top screw, bottom screw and 1 middle screw once the servo plate is installed (leave the rear passenger compartment side middle screw out) this the screw that you likely drilled a hole in the support to remove earlier.
34. Connect up the servos to the harness and test
35. If you have binding its most likely in the lower linkage that controls air flow to the rear passengers (you can get lucky and slightly pry towards drivers side of the servo plate away from the heater side while trying to move this linkage into alignment. (you can also see the alignment peg through the area where the cubby was removed earlier but not well). This is how I finally found what alignment I needed (do your self a favor now and take a sharpie and make alignment marks for the future.
36. If no binding and full operation is restored your done, otherwise remove the servo plate and realign and try again.
37. Once eveything is working reinstall everything previously removed in reverse order.

**Note everything I removed doesnt have to be taken off but you'll thank yourself in the end if you remove it first, I didn't but later did because there just isn't any room to work or see what your working on.

Took me a total of 12 hours to do this, but Toyota will charge in excess of $2k for this same work if they will even attempt it.

Also the servos rarely go bad but are just bound up by the gears so dont freak out if there is zero movement clear the bind and you'll likely be good.

**Note before testing I recommend checking for slight play in all the meshing assemblies before doing and operational test it can speed the process as if it binds you'll likely have to remove everything and realign it again. If you dont have a little play it will likely bind to play with the servo plate alignment before testing so you only have to adjust the gearing on the heater box to mesh properly with the servo plate and not realign the servo plate now.

Happy Head banging!! If your like me you'll be an expert at this when your done, but hopefully this will save someone some time and an expensive trip to the dealer.
 

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Sub'd. Thanks to those contributors who are posting good pictures and steps they took to troubleshoot with tips and tricks! I'll be digging into a similar issue on my new to me 07 SR5 with no heat to the passenger side and poor control of air flow direction, seems to be weak out of the main vents and leaking off to others no matter where I turn the dial. I'm hoping to find that I just had a wire pinched in the gears, it appears this dash has been apart a couple times before me, then just reset timing and it'll all be good, fingers crossed.

Edit: Found a broken blend door shaft on the passenger side. The shafts are plastic! I ended up ordering a used bare heater box for $275 on ebay so now I get to pull my whole dash off to transfer heater core and servos over it.
 

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Had the same thing happen to me as of about a week ago. The vents are currently stuck on defrost (output from top of dash). I've felt that there was something wrong for the past couple of years or so as I had been hearing noises coming from the dash like something was loose in there. Hard to describe the noise but it sounded kind of similar to a very slight rattle or as if there was something that was not quite in place, like something was loose. As of the last month or two, I started getting noises inside the dash that sounded like motor(s) moving or attempting to move whenever I turned off the truck that would go on for at least 10 or 15 seconds. Now, it's just stuck in defrost mode, which is fortunate that way I can at least ensure I can drive without a fogged up windshield. Will have to research this some more but the above comments don't look promising. Truck is a 2008 base model.
 

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I've known something wasn't right with my Tundra's HVAC for the past few weeks and just never thought to dig into it because I've been so busy. I decided to Google my problem while stuck in traffic today and look what I found...

Heater stuck on defrost - TundraTalk.net - Toyota Tundra Discussion Forum

Unfortunately, they make no mention of a fix. The problem I am having is this. I can change fan speed, temperature in both zones, etc. but I get no air out of the vents on the instrument panel. The mode select swaps the zones on the screen, but does not change where the air flows from. The only vents working in front are the two on the top of the dash for defrosting the windows and the big one in the middle to defrost the windshield.

It is going to get really hot, really soon down here and I am praying that the "brain" of this HVAC control hasn't died on me. I have pulled the Nav head unit out several times, but I pulled the whole thing apart this evening and unplugged and re-plugged all connections to the HVAC controls and it still will not function properly. No wires were pulled loose either.

Anyone else experience this? What was the solution? Thanks!
I am having the same problem, I was hoping to find a simple fix or answer too how I can fix it for summer is here and rolling the windows down won't cut it.... best truck ive ever owned minor problem, need some insight plz
 

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I am having the same problem, I was hoping to find a simple fix or answer too how I can fix it for summer is here and rolling the windows down won't cut it.... best truck ive ever owned minor problem, need some insight plz
You need to take the servo plate off to find the problem. I had a broken plastic lever shaft I had to epoxy back together. I will post a DYI hack in the next.
 

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Here is a hack for anyone that breaks a plastic shaft for a lever on the Hvac assembly.

1) Drill a 1/8 hole into both side of the broken shaft on both sides. The depth depends on where it snapped.
2)Go to hardware store and pick up 1/8”-12” round bar and JB weld epoxy 5 minute quickset.
3)Cut round bar to desired length. Epoxy bar into place on lever side- let dry for +30 minutes.
4)Epoxy other side of bar and push lever into shaft- let dry +1hr
5) reassemble.
I hope I save you from ripping out the whole dash and spending +1000 for a new HVAC assembly. 😀
152339
152340
 

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Had the same thing happen to me as of about a week ago. The vents are currently stuck on defrost (output from top of dash). I've felt that there was something wrong for the past couple of years or so as I had been hearing noises coming from the dash like something was loose in there. Hard to describe the noise but it sounded kind of similar to a very slight rattle or as if there was something that was not quite in place, like something was loose. As of the last month or two, I started getting noises inside the dash that sounded like motor(s) moving or attempting to move whenever I turned off the truck that would go on for at least 10 or 15 seconds. Now, it's just stuck in defrost mode, which is fortunate that way I can at least ensure I can drive without a fogged up windshield. Will have to research this some more but the above comments don't look promising. Truck is a 2008 base model.
I have the exact same symptoms. Were you ever able to fix this issue? This thread is extremely informative.
 
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