Changing climate controls

Curious if anyone has upgraded their climate controls. I’m considering upgrading my manual SR5 controls to something with auto features if it’s a simple project.

 

It's not simple on the 2nd Gen, I wouldn't think it would be easy on the 2.5 Gen...

 

It's not a small undertaking. This should give you an idea of what you are in for.

https://www.tundras.com/threads/gen-2-auto-ac-upgrade.90972/#post-2290878

 

Yeah, I saw that thread just now on the 2nd Gen, I was hoping the 2.5 Gen would be easier. One would think Toyota would make everything the same and just swap a panel.

 

Oh, I didn't know there was a thread here...

 

Seems like an interesting project, but doesnt appear to be the easiest.

 

yeah, I’m considering it anyways if I can find the info on the 2.5 Gens. Will be worth it as I plan on keeping this truck till it dies.

 

@RainMan_PNW have you got any advice or instruction on where to start? I linked your post to the previous gen stuff, but I also know you're an electrical wizard.

 

It has been done - I’ve read about it somewhere. Unfortunately, there’s more to it in the Gen 2.5.
The Gen 2 has a dual zone air box on all the trim levels. The Gen 2.5 is single zone on the trims with manual controls. So you are missing some blend dampers that are servo controlled. To do it “right” you would need to swap out the air box, which requires damn near a full dash dismantle.
The rest of the process is essentially the same - swap the “amplifier” and controller, add missing servos with new wiring harness, install thermistor and venturi, etc.

I can look at the EWDs a little later and post up some more specific details

 

UPDATE
I’ve been doing a bit more digging, and it might actually be closer to the process in the Gen 2. Without a guinea pig to try it, I can’t say for sure. Digging through the wiring diagram, the differences between “Auto AC” and regular are similar/same as they are on the Gen 2. Below images are the 18-21 EWD, but 14-17 are similar except the solar sensor is directly part of the circuit in the 14-17 trucks like in the 07-13 (in 18-21, the solar sensor info is sent via CANBUS to the AC Amplifier):

The dedicated room temperature sensor that is tied into the system (denoted with *1 to indicate trucks with Auto AC)


The “blower assembly” diagram showing the Air Cooler Bypass servo motor (again denoted by *1 to indicate Auto AC)


The rest of the “blower assembly” diagram


Here is what is interesting here:
The diagram shows an Air Mix Driver Side and Air Mix Front Passenger Side servo motor, even though the truck doesn’t actually have dual-zone climate control. There is no (*) denoting any feature variations that would indicate one or the other servo is feature specific.

Armed with this, I jumped over to parts.toyota.com to sift through what shows there for available parts using a 2019 CrewMax SR5 as the selected truck. Getting into the Heating and Air Conditioning Cooler Unit diagrams, the two diagrams are similar to what I saw in the 2007-2013 when doing the swap on my truck
Lower Trim shows this


Higher Trim shows this


The important thing here is looking at two key components - 87050 (the core/case housing) and 82210K (the wiring harness for the servos). Looking at the 87050 link on that parts list shows a bunch of different options with different prices, some of which are for Gen 2 and some for Gen 2.5, some for DC, CM, RC, higher trims, others for lower trims, some for “rental” or “fleet” options, etc. In particular, I found that 87050-0C100 is for 2014-2021 trucks that are SR-5 trim (under the “What this fits” tab) and is MSRP $862. The 87050-0C110 is for the higher trims in the same years and MSRP is $1257. That seems like a significant difference, but you can see in the above diagram that the servos and venturi are part of the entire 87050 assembly (or can be bought separately, but the housing can only be bought with them attached).

Next, I turn my attention to the 82210K harness. This time, there are only three options. One of those shows only 2007-2013 SR-5 and Grade trucks in “What this fits,” but the other two are specific to 2014-2021 trucks, and one lists only SR-5 and Grade trims, while the other lists Limited and higher trims - specifically 82210-0C020 is for the higher trims and MSRP is $29 (looking back at my Gen 2 thread, this is the exact same part number as the one in the Gen 2). What is odd here is the lower trim wiring harness 82210-0C040 has an MSRP of $161!

OK - without actually seeing a photo of the 82210-0C040 harness to confirm it has plugs for 4 servos, or without actually looking up under the dash of a Gen 2.5 truck that is manual AC and counting the servos that are there, I can’t fully confirm that the core housing has the capability for dual zone and just isn’t actually using it (or, more correctly, it has dual zone but the two are being controlled as one). I do know that the system will not work if one of the servos is not plugged in or is dead (this was through testing when I did my AC swap in my Gen 2). And the wiring diagram shows 5 servos for Auto-AC and 4 servos for standard (no different than Gen 2). This leads me to suspect that the swap for Gen 2.5 is going to entail essentially the same process as the Gen 2 (albeit with different part numbers for the amplifier and controller).

 

One other thing to note - something I found when doing the swap on my Gen 2 - is that the difference between the core housing on the Double Cab and the Crew Max has to do with whether the openings at the bottom front are cut out to send air through the ducts in the “hump” back to the rear seats in the center console.

At one point, I ALMOST pulled the trigger on a Crewmax center console and ducting parts to put rear center air in my old Double Cab.

 

So, I have a 2021 limited, and actually want to convert the other way to the SR5 climate control. I had a 2018 sr5 and loved the simplicity of the three knobs vs what I have now. I also prefer the older head unit.

Am I crazy to assume it should be easier to “downgrade?” Just cap some stuff off and leave it in there unused?

 

Yes and no.
In theory, you'd need to do a similar swap in reverse - change out the "amplifier" (ECU), controller, and servo wiring harness so that it skips the one damper servo. But that's where things start to potentially have issues... the damper servo that is skipped will need to be set to a neutral position and then will no longer operate. And you'll lose your seat heaters since their buttons are integrated into the higher trim controller. You might be able to require those to aftermarket controller buttons, but not 100% sure.

 

@RainMan_PNW did you end up upgrading your '21 from manual to auto AC? Or did yours already come with it? I've had my truck for less than a week and I already miss the automatic AC that *all* of my other vehicles have / had, including the last 3 trucks. As much fun as it is to constantly fiddle with the temperature dial...
So, I'll be attempting this.
Here's what I gathered for the part numbers so far (multiple numbers if there is an old / superseded part number that would be equivalent):

Controls:
Platinum crewmax (heated + ventilated seats): 55900-0C060/55900-0C190
Limited Crewmax (heated seats): 55900-0C120; 559000C180
Limited Double Cab (heated seats): 55900-0C090/55900-0C170
SR5 (non-heated seats but still auto? maybe? can't find any used photos to verify): 55900-0C270

ECU:
Platinum/Crewmax: 88650-0C400
Premium/Crewmax: 88650-0C410
Premium/Double Cab: 88650-0C420
Limited/Double Cab: 88650-0C530
and and and there are so many different ones. if only we could just flash the module we already have with different code...

Harness: 82210-0C020
Servo / damper for cooling unit: 87106-0C100
Aspirator: 88897-08040; 88897-32090
Thermistor: 88625-06040; 88625-47021
Hose / air: 87233-0C010

 

My TRD Pro came with them.

 

I just did a combination of this over the Christmas break. I mainly used the 2Gen thread posted by Casey above.

My truck has the 2007 HVAC box which means it is dual zone. I am using a 2015 Amplifier and Control panel and everything is working fine. I have full temp control over both sides with the digital display and auto functions.

The problem for anyone in a 2014 and newer truck is that all the trucks with the manual AC controls are only single zone HVAC boxes. This means you can do this swap and probably getting it working but you will never have the ability to adjust different temps for driver and passenger. The driver side temp setting will be what the passenger is stuck with no matter what the display on the controller actually reads.

The only way to properly fix this is to pull the entire dash out and swap in a dual zone HVAC box.

 

Have you seen this in person? I have seen a lot of people saying it is the case, but all of the comments have been anecdotal, not referencing actually having their hands on an HVAC box.
At the same time, pulling the whole dash to swap the box sounds like a fun afternoon to me, and it would give me an opportunity to properly fully clean out all the cig smoke/ash from the previous owner.

 

Yes I have a 2015 HVAC box in my garage right now in pieces. The Blend door is one solid piece controlled by one servo motor.

The Dual Zone Box has a divide in the center of the blend door and each door is controlled by an individual servo.

To get the HVAC box out you basically have to remove everything all the way back to the firewall. It is a big undertaking.

Here are pictures of the 2015 HVAC box from a week or so ago. You can see the blend door is one piece. It only has gears and controls from a servo on the driver side. https://www.tundras.com/threads/please-help-identify-hvac-noise.118582/#post-3047131

 

Okay, well that's frustrating. I'd probably be okay with just one actual zone, but a missing servo will throw errors, so maybe I should just buy a complete used unit.
Any chance it can be disassembled in the truck (with the dash pulled that is) and the blend doors swapped so the AC and coolant don't need to be evacuated?

 

Would be surprised if your HVAC box had the gear assemblies on the passenger side for the servo to connect too.

I think you can just plug the passenger servo in to the harness, let the ECU think it is controlling something when it actually isnt hooked up.

You would just have to remember an temp adjustment made for driver side is controlling passenger side also. You could turn the dial and change the numbers for the passenger side, it would move the servo but the servo wouldn't he connected to the blend door so you get no change.

 

That would probably be fine tbh. So the 2015 airbox just has no servos at all on the passenger side? I'm going to go take a look at my airbox when i next pull the dash apart, next couple of days

 

Mine shows the housing cast for room for the servos and gears but they are not there.

The only servo/gear assembly is on the driver side.

I looked at little closer and it’s two separate blend doors in side but they are connected together by one long main shaft.

The main shaft is the point of rotation of both ends shown by the red arrow. The blue arrows show the approx range of motion on the passenger side. The servo and gear would be sitting right here.

 

I think you could do the swap but the driver servo would be the only one controlling temp for the entire truck.

You would have to have the passenger and other servos plugged in to keep the amplifier happy and retain memory settings.

I assume the auto function would work just fine. It would be like you had the sync button pushed and activated on the control panel all the time

 

For sure all the servos would need to be there and plugged in or the system will go into fault mode. But, as Jeff said, you could do it in such a way that the passenger servo (and the defrost blend, which is the other service originally part of the auto system that is not on the non-auto trucks) are basically moving but not actually adjusting anything.

 

Excellent, thank you both!
I think I will start there, since I can do that without a full dash disassembly. I have an amplifier and controls on the way, and will order the other pieces (aspirator, thermistor, hose, harness, two servos) in the next few days. I'll zip tie the two servos up under the dash, and then maybe over the summer disassemble and steam clean and dynamat and split the driver/passenger/defrost blends, and just keep a lookout for an auto housing with the gears. If the one from the earlier trucks is "the same", those are a lot easier to come by...