*VERY* occasional HVAC malfunction

I got into my truck this afternoon and started it up, and didn't see the 'little man' in the HVAC display (the one that indicates where the airflow is going). (FYI, I've got the dual-climate system.) I then noticed that despite being set to the front dash vents, the air only blew out of the top dash vents (e.g., defrost).

I've owned my truck (2020 CrewMax) since mid-March; and I've only seen this happen two times, and both times it's resolved itself with a truck stop/restart, so I'm not too worried about it. Still, I'm curious as to whether or not anyone else has run into this, if it's all that common, etc.

 

Haven't run into that issue, but I would definitely get that sorted under warranty.

 

I remember seeing another thread about this a few months ago. I think he took it in and they replaced the thing that selects where the air goes behind the dash, but don’t remember the details. Try to search and maybe it’ll be the same as your issue.

 

If it's still on. Take a video of it. If it go away who knows when it will come back. If you have video of it, you can show it to the dealership.

 

Definitely take a video of it because it’s so random. The dealer will fix it based on the video if they can duplicate it

 

That sounds like a blend door issue .

 

Well, that's what I'd normally think. However, both times it happened, I've noticed a few things:

1. Other things occur (e.g., the screen showing the vent door position malfunctions).
2. If I turn the truck off and back on, it works just fine.

In other words, it may be a blend door issue, but it almost 'feels' like an electronic issue as well. (On a side note, if I CAN'T fix it under warranty since it happens so infrequently, I wonder if I can eventually just replace the dual climate control with your standard knob HVAC controls.)

 

I will once I can get it on video again...may take a few thousand miles.

 

I have a 2020, and no HVAC issues...

-T

 

I wasn’t sure about the tundras but with Ram if it’s a blend door issue they usually just have to reflash the computer to fix it .

 

That's good to hear. To be clear - the actual AC/heat itself works just fine; it's just that the 2 times I've seen things go on the fritz, it would only come out the top dash vents.

I'll likely just wait until the next time it happens, and then will drive straight to the dealership to have them capture it after taking a video or two.

 

Update:

So it happened for a week straight during *that week* (anyone who got caught in the last storm KNOWS what I mean). Heat worked fine but it defaulted to the defroster, period. Of course, after an entire week, literally as soon as I brought it to the dealership, it worked fine. I was SUPER pissed. I had to reassure them I was pissed at it 'working fine' when I brought it in.

They told me they'd call the 'regional Toyota FTS' (unsure what that means). They just got back to me and told me that there are some initialization tests they can run to determine specifically what component is screwed up, so they can then replace those components, and not just shotgun the whole thing. Got an appt. for next Monday, and then they'll hear back once they provide the findings to the FTS.

I have to admit that I thought dealerships themselves could (and had the resources to) troubleshoot this sort of stuff.

 

FTS is a field technician. When us normal technicians have a problem like this we can't figure out, we have an FTS agent come out to the dealer and he's able to pull more strings with Toyota. Since this problem is so intermittent and those components are so expensive for a vehicle under warranty, Toyota wants the FTS to document everything going on and do advanced electrical diagnoses that they are trained to do before Toyota pulls the trigger on warrantying a $2k AC amplifier.

 

Toyota has gotten very careful with warranty stuff recently and they have to make it a huge deal to replace big stuff under warranty. There's a lot of things that come into the dealership where we as technicians know what is wrong, we just can't prove it to Toyota because it's intermittent and therefore we can't get the approval to replace it. Everything has to be documented and we there's a checklist of things we have to do in order to warranty something.
The FTS agents get paid to diagnose this sort of stuff so that's why the FTS is called in to do more difficult warranty diagnoses instead of the normal dealership technician cause we don't get properly paid for warranty stuff.

 

Just hope that if they have to replace something it is small and can be accessed easily. If the rod to you blend door decides to take a crap on you it is a very unpleasant and costly situation. Even more so if you are out of warranty.

 

Thankfully, it's definitely under warranty; it's a 2020 purchased last March, and it's only got 16K on it.

 

That makes sense, and I can appreciate it. It just frustrates me (as an IT guy) that I can literally document what happens every startup/shutdown (e.g., what temp/fan position/vent position/etc.), what the temp inside/outside is, take videos.....and none of it matters because "Well, the truck wasn't here." I know why they say that; and as a nerd I can't disagree with it, but it doesn't mean it's not frustrating. LOL

 

Update: Brought the truck in for whatever test the FTS guy recommended, and *bingo* they found a servo somewhere that was either failing, or wasn't putting out correct voltage, causing the HVAC system to fail to default. The part will be in tomorrow/Wednesday, at which point they'll repair it.

Only took almost a year to find it! LOL

 

Update: Fixed!

So they replaced the part; took them about 3 hours or so. As soon as I went out to start the truck it did it again.

Went back in and they said "Well, OK, let us call the FTS guy again and we'll let you know."

In the meantime, I drove it for the next week or so....and it worked great. Turns out that's because once they replace that specific part, it does that 'diagnostics check' once more, and I guess it found everything in good order because it's not done it since.

 

Posting again on the outside chance that anyone else has this issue.

So after 10 months, the issue appears to be back....on the coldest day of the year so far.

Not sure exactly what the issue was, as it was fixed for 10 months, but I found these posts out there, in case anyone else has the same issue. I'll be calling the dealership Monday to report this issue. Climate Control System Delay after Startup | Toyota Tundra Discussion Forum (tundratalk.net)

The part that was replaced was the "Damper Servo Subassembly."

2020 Toyota Tundra Servo sub-assembly, damper. Air, conditioning, conditioner - 871060C090 - Genuine Toyota Part

 

@Kung sorry your issue has come back. I just went thru this same thing on my 2017 1794. The air would only come through via defrost and the climate controls wouldn't respond for the first minute of startup. After running for a minute, the climate controls would turn on and properly adjust hot and cold but only come thru defrost.

The fix for mine was $5k of warranty work paid by Toyota. Dealer had to remove entire dash and replace the blend doors, amplifier, and some other component in the system (can't remember exactly what it was right now). That was about a month or two ago and (knock on wood) it's still working.

I can find repair paper work later if that helps.

I also found that our Tundras have a very accessible way to print out error codes on the climate control. Next time this issue happens, press and hold the Auto & Air recirculation buttons on the climate control for 10-15 seconds. Eventually it should flash a couple of times and print out some error code, 2 digits at a time.

Hope the dealership is able to properly fix it this time.

 

Sorry to hear about OP's situation and others who have had to deal with HVAC problems at the dealer.

My 2019 Platinum's blend door made squeal/grind noises 1min. after turning off the ign., I started having the dealer look into it last April but the issue was so intermittent they "could not replicate" it. Maybe a door or airbox is out of spec and tearing up the OP's servo assembly?
On it's 3rd trip back in Dec. they replaced entire airbox assembly under warranty, turned out it would do it more frequently when cold. Lets hope it lasts, my 36K runs out in a few 100 and there's only 12mo. warranty on the new airbox.

Important thing is to keep getting the issue documented while its under warranty, having a known issue that wasn't addressed after the warranty expires might save some $.

 

I had a blower motor issue and I recorded it. When I went to the dealer they said they couldn't use it to fix the problem for warranty purposes. Just fyi

 

@MyActualName - $5K?! Holy crap. Yes, please do share the paperwork you have. The issue was first reported with something like 6K on the odometer so I’m not too worried about support, but I’ll likely upgrade the warranty after hearing this tidbit. LOL

 

$5K is massively inflated. Should be more in line with $2700-$3000 total which includes approx $1800 in labor.

 

Well yeah, I figured somewhat. If I had to have something like that done after warranty I’d likely find a specialist I trusted to have them do it.

From what I understand this problem is not exactly common…but I sure hope it’s not a harbinger of things to come.

 

@Kung and @Sundog I'll dig out the paper work later this week. Because I paid $0 for it there isn't a total on it. You're very much correct the price was probably inflated.

It did take a tech 3 days to do. Pretty sure the dealership I went to doesn't do this kind of work very often and the tech definitely ended up working overtime on it.

 

Appreciate it. I do know that they had to dismantle my dash last time (leading to some creaks and squeaks in my dash), but not sure they replaced the whole shootin' match.

 

In this particular case I'm 'good to go' in a sense; I originally had an issue that cropped up around a few months after I purchased my vehicle (in March of 2020), and after chasing it down FOREVER, it finally actually failed on them while onsite, and I had the 'damper servo subassembly' replaced in March of 2021. That's on file with them, so there's already a precedent, thankfully.

With that said, while the dealership obv. has to wait until 'they see it' they've already told me that because it's been reported AND they've seen it happen, while they have to see it happen to be able to diagnose, it's covered if I report it while in warranty.

 

Did it again this morning. I ran the following procedure, and while it provided no error messages...it also didn't 'test' every vent, like it said.

(Or rather, it *DID* test them, but air did not blow out every single vent....only the defrost vents.)

• Hold down the Recirc and Auto buttons simultaneously on the Climate Control panel.
• While holding them down, turn the key in the ignition to ON (or press the ignition button twice)
• The digital screen will begin to blink, and will display a # or multiple #'s in addition to other symbols. The #(s) is or are generic error codes.
• Press the Recirc button again, and the system will conduct a self-test, testing every vent. Mine conducted the test and gave no error codes but not every vent blew air.

Given that, when I turn my truck off and hear some creaking and the like of vents w/in the dashboard...I'm wondering what the issue might be.