100 Series NAV Delete – True Standalone HVAC Solution (OEM+)

[Anarchy]

The A/C amplifier itself isn’t being replaced or replicated, it remains the factory control module.

Reproducing the full A/C amplifier logic would be a much larger scope and introduce significantly more complexity and risk.

 

[LJE]

Just copy/rep the AC amp circuit board, two versions complete the 100 series. The connectors are universal, the hard box is standard for all years. The wiring is known.

The effort is admirable. A soft solution is preferable. At 2000usd, it isn't.

I've never cracked open an AC amplifier to see how complex that board is, but you'd still have to replicate the firmware that lives on that board... I may be entirely incorrect (much more profieicent in the mechanical realm these days), but I'd suspect that getting the board layout & firmware correct on the AC amplifier is probably more complex than just figuring out the comms to just control the factory AC amplifier.

Not to mention I bet you could make the HVAC system do things that it really shouldn't do in the process of getting said firmware correct, hahaha. I assume a lot of the failsafes/limits are built into the AC amplifier so if you try to command something dumb it'd prevent it.

Again, just a dumb (mostly) mechanical engineer here, so could be off base. Just seems like reverse engineering the comms protocol to control the AC amplifier would be easier than reverse engineering the AC amplifier itself...

 

[jerryb]

isn't reverse engineering and copying two different things?
If you order enough of the 60b80 variety you can get the for less than 200usd

 

[JAntosch]

Successful command injection with the HVAC command set mapped and confirmed under controlled testing.
Now validating full standalone operation without the OEM NAV/MFD connected, including startup behavior and power-cycle stability.

The goal remains:
OEM-style physical controls
No screen
Plug-and-play

Curious to hear from those following the development:

- If you could completely remove the factory NAV screen, run any head unit you want, and relocate HVAC to OEM-style physical controls in the lower dash - would you choose that over current Teyes/Grom/Android options?
- And honestly, what would make you NOT buy something like this?

Appreciate the feedback. This community has been a big part of shaping the direction.

Currently have the Teyes, and while it is the least bad option in my opinion, I would much prefer OEM-style physical controls over the touchscreen interface. May or may not replace the headunit as I like the large screen for maps etc.

Exorbitant cost and cutting into the factory harness would really be the only turn-offs, plug and play would be greatly preferred. If possible, integrating a RAM mount into OEM-style physical controls section would be phenomenal as the tape deck RAM mount is a great place for the phone.

 

[Formerjeeper]

Successful command injection with the HVAC command set mapped and confirmed under controlled testing.
Now validating full standalone operation without the OEM NAV/MFD connected, including startup behavior and power-cycle stability.

The goal remains:
OEM-style physical controls
No screen
Plug-and-play

Curious to hear from those following the development:

- If you could completely remove the factory NAV screen, run any head unit you want, and relocate HVAC to OEM-style physical controls in the lower dash - would you choose that over current Teyes/Grom/Android options?
- And honestly, what would make you NOT buy something like this?

Appreciate the feedback. This community has been a big part of shaping the direction.

Q1-yes this is the ideal scenario and I'd absolutely choose this over Teyes/Grom/etc. I have a Grom but the ancient screen is painful and it's sometimes glitchy with reverse cam etc. I have considered Teyes but the potential for HVAC control issues has prevented me from going that route.
Q2 - three things could prevent me from buying this: (1) complex/irreversible installation, (2) finished buttons/interface is ugly or mismatched with the existing 100 interior design, or (3) price is crazy.

 

[jerryb]

I still don't get the FW aspect. Replacing an amp in any year with another works in every instance. You're deleting the whole MPX system with screen removal.
Im not a PE, so assume I know know nothing. If I'm totally wrong, school me please.

 

[y5359]

isn't reverse engineering and copying two different things?
If you order enough of the 60b80 variety you can get the for less than 200usd

so you are saying if we order enough we can get the 60b80 boards made? Any info on how many would need to be ordered?

 

[Anarchy]

The amplifier contains the control logic for compressor protection, blend door control, sensor interpretation, fault handling, and operating limits. That firmware isn’t just a passive board layout, it’s the actual HVAC control system.

This project isn’t replacing the A/C amplifier. It’s removing the screen as a user interface layer and communicating with the existing amplifier so all of Toyota’s control logic remains intact.

Replacing the amplifier would mean reproducing the entire HVAC control system rather than just the interface to it, which is a much larger scope.

 

[jerryb]

dude, you sound like my PM.
derate the complex lift because you in no way will lift over 100t.
And to be serious, then copy, COPY the board, not some bits, all bits.

 

[LJE]

I guess I'm still confused at what just copying the AC amplifier would do? You'd still need to figure out how to communicate with the copied amplifier, no?

Again, haven't dug in (at all) what the non-nav HVAC control panel outputs, but I sorta doubt it's basic switched lines for each individual control.

 

[Coin]

I guess jeryb is assuming the non-nav hvac controls are readily available and that is what we would use instead.

 

[jerryb]

Yes, for the most part.
what I would say is that if you copied the board, or bought 50-100 of them, then everything else would line up. The capability is there. Decoding everything and putting it in a box makes the wiring a nightmare. I'm not advocating either way. The effort as stellar, the info gained is valuable. The majority of people don't care- because they don't read anything and want a plug in fix. I am jaded or sure.

 

[Anarchy]

That’s fair, and I agree most people just want something that installs cleanly and works without having to source parts or build harnesses.

That’s really the focus here.

Going to shoot you a message @jerryb , I have some questions regarding compatibility across years.

 

[Anarchy]

We’ve made solid headway on the communication side. The system is now consistently reading and responding to the factory HVAC network, and we’ve confirmed that both command and status messaging are present and usable with nav screen fully disconnected. That was one of the bigger unknowns early on.

We’re now moving into refining how the system interprets and tracks HVAC state (fan, mode, etc.) and tying that into the physical panel controls. The goal remains making everything feel as close to OEM behavior as possible.

More updates soon as we dial things in.

 

[BlizzardBird]

Very cool project...excited to follow along and read these updates. Do you have a background automotive base software?

 

[Anarchy]

Small update on this... took it a step further and filed provisional.
This is happening.

 

[Sunman]

So can you describe exactly what you are doing here in layman's terms? I have the same vehicle as the one you are working on. I'd love to find someone who can tell me the options that are available- I think I've look at all of them and none so far seem to be what I am looking for. The 2006 digital screen is pretty primitive so anything using that is a no - go, and I am not a fan of the Tesla screens. I actually bought - but haven't installed a robofinity infra red camera that mounts to the hood and sees heat on the side of the road at night. I live and drive a lot in a rural area with a lot of deer, and this would be a cool addition, but the screen that comes with it doesn't have a lot of adjustments, and I'd like to find either an indash or top of the dash replacement screen that has multiple video inputs..... I'm guessing you are not going that far, but just building the harness to do the adaption? Any recommendations on any head unit top of the dash monitor that has mulitple videos in? I would think someone will come out with that soon so people who want multiple exterior cameras could utilize them. Probably not the right forum to ask this, but figured maybe somone woulld know other options.

 

[Anarchy]

So can you describe exactly what you are doing here in layman's terms? I have the same vehicle as the one you are working on. I'd love to find someone who can tell me the options that are available- I think I've look at all of them and none so far seem to be what I am looking for. The 2006 digital screen is pretty primitive so anything using that is a no - go, and I am not a fan of the Tesla screens. I actually bought - but haven't installed a robofinity infra red camera that mounts to the hood and sees heat on the side of the road at night. I live and drive a lot in a rural area with a lot of deer, and this would be a cool addition, but the screen that comes with it doesn't have a lot of adjustments, and I'd like to find either an indash or top of the dash replacement screen that has multiple video inputs..... I'm guessing you are not going that far, but just building the harness to do the adaption? Any recommendations on any head unit top of the dash monitor that has mulitple videos in? I would think someone will come out with that soon so people who want multiple exterior cameras could utilize them. Probably not the right forum to ask this, but figured maybe somone woulld know other options.

What I’m doing is decoding the HVAC communication from the NAV/MFD and recreating it with a standalone controller. On these trucks, the screen is apart of the HVAC system. Removing it breaks that communication. This replaces that functionality at the protocol level, so the system works without the factory screen.

After that, you’re free to run whatever display you want in its place.

 

[Sunman]

awesome... any eta on completion? Is the hole in the dash where the screen sits a standardized size? So with your controller, you'd take the dash apart, disconnect the stock head unit, and install another using your controller as a collaborator with the HVAC unit, with standard hookups for all the audio pieces?
Would there be a special way to mount the chosen head unit, or is it something that is standardized?

 

[TurboJAM]

awesome... any eta on completion? Is the hole in the dash where the screen sits a standardized size? So with your controller, you'd take the dash apart, disconnect the stock head unit, and install another using your controller as a collaborator with the HVAC unit, with standard hookups for all the audio pieces?
Would there be a special way to mount the chosen head unit, or is it something that is standardized?

I believe it’ll make this setup (see pic) easier to install.
At the moment if you fit a double din display you lose Air Con controls as those buttons are on the OEM sat nav display.