DIGITAL car A/C unit control

warewolf · 08-20-2005, 04:22 PM

Ok folks, here's a challange for you: Computer Controlled AC, when the factory unit is digital (20+ wires plugged into the back of that sucker)

In my 2001 Toyota Camry, I've got a digital AC unit that has two connectors in the back. During my playing around w/ it I've discovered that if the AC control unit is unplugged, that it must be plugged back in when the car is POWERED ON, or else the temperature sensor gets out of whack and the control unit thinks that it's ****ing hot outside, and constantly blasts cold air.

I've

ed

ed and found nothing related to the markings on the AC unit itself, "TOYOTA", "55900-33250", "146430-7732" "12V 3 C", "DENSO". (Until now, I had no idea that Toyota/Denso were related

Like other people on the forum, I could squeeze in the CarPuter in the dash + LCD if I. could. only. toss. the. AC. unit.

Any ideas?

kickercivic1 · 08-20-2005, 04:34 PM

STOP YOUR BS, you didn't search. There is crap load of thread going on this.

WxGuy1 · 08-20-2005, 05:00 PM

Kickercivic1 says that, I presume, because there's a HUGE thread about this... it's only a few threads down from this one... has 227 replies... http://www.mp3car.com/vbulletin/showthread.php?t=50365

warewolf · 08-20-2005, 05:54 PM

Quote: Originally Posted by kickercivic1

STOP YOUR BS, you didn't search. There is crap load of thread going on this.

Thanks for not reading my post! I said that my AC unit is digital, not one that has a few wires for fan/compressor/etc. There are a ton of wires coming out the back of my AC unit. It has no knobs. It's all digital. I don't have a digital camera, otherwise I would have snapped a photo of it. The fact that the AC controls go whacko when the AC control unit is unplugged with the power off means that it isn't your standard "turn blower on, turn AC on, turn rear-defrost on" throw-a-relay type unit. The unit has some brains in it, that get confused if it's unplugged w/ the power off. I havn't the foggiest idea what the pinout on the two connectors on the back are. I'm probally going to call Toyota on Monday and see if I can weasel them out of them.

And yes, I read http://www.mp3car.com/vbulletin/showthread.php?t=50365, which is why I had DIGITAL in the title of my post. The digital part I'm talking about is the factory AC control unit, not a "digital" homebrew controller board. I apologize if I wasn't clear. The homebrew HVAC control unit that was made by Maestro will not work for me. I wish it would.

P.S.: thanks for the respectful (and informative!) response.

kickercivic1 · 08-20-2005, 10:03 PM

You have to come up the whole thing yourself. this is custom. Can't be just plug and play.

warewolf · 08-20-2005, 11:17 PM

Quote: Originally Posted by kickercivic1

You have to come up the whole thing yourself. this is custom. Can't be just plug and play.

You have to be one of the most unfriendly people I've come across on this forum. Thanks for not helping. In the future, instead of flaming someone on their second post on a forum, a little more respect would get you a long way. When I figure this out, you can be absolutely sure that I will not be sharing the information I've gained with you. You can consider yourself persona non grata. I've read a lot of threads on this forum. This forum itself is a great resource, with software, hardware, and detail work hackers, and that alone is one of the reasons I finally decided to install a computer in my car. I posted asking for help, because there was a high probability someone else would be doing the same here. Good day.

warewolf · 08-20-2005, 11:27 PM

Quote: Originally Posted by WxGuy1

Kickercivic1 says that, I presume, because there's a HUGE thread about this... it's only a few threads down from this one... has 227 replies... http://www.mp3car.com/vbulletin/showthread.php?t=50365

Yeah, that post is a great resource for someone who has dials/knobs on their AC control unit; my unit looks like it's quite a bit more advanced than that. :/ This looks like it will be an adventure-and-a-half figuring this out

I've emailed Denso, looking for information on how to interface with it. Hopefully they'll be forthcoming with information.

WxGuy1 · 08-20-2005, 11:55 PM

Yeah, I imagine it'll be quite an undertaking. If it really has like 40 wires from the back of the HVAC unit, then I'll wish you luck!

:-)

Stacker · 08-21-2005, 12:15 AM

Most everyone is very friendly her I am sure you have read that by now. I am interested in what you are doing. I do not have a Toyota but I greatly enjoy learning how people overcome their issues, and the methods they use for modding. Please if not for any other reason, reply so that myself and WxGuy1 at least learn from your route. I would appreciate it and wish you the best of luck figuring out your wiring mess.

Mastero · 08-22-2005, 02:44 AM

ok ... i think i know what you require.... all you require is relay board controlled where you can imitate the button press with some kind off relay toggle. This can be done using PIC1877 where you can get 33 i/o and one input for serial connection. this way you can just controll the OEM controlls ... but remember the wire needs to be connected to the main controller else it will not function... all you have to do is find the wires and connect it . SORRY for the jumble post my enter key is not working..

warewolf · 08-22-2005, 08:53 AM

Quote: Originally Posted by Mastero

ok ... i think i know what you require.... all you require is relay board controlled where you can imitate the button press with some kind off relay toggle. This can be done using PIC1877 where you can get 33 i/o and one input for serial connection. this way you can just controll the OEM controlls ... but remember the wire needs to be connected to the main controller else it will not function... all you have to do is find the wires and connect it . SORRY for the jumble post my enter key is not working..

Slick idea, I might end up doing that if I can't get any information out of Denso -- I got a reply from them today:

Quote:

Thank you for your mail and please contact the following aftersales section
in U.S.A.
There are many staffs for answering questions about our specification and
the like.
U.S.A.　　　　　　DENSO SALES CALIFORNIA, INC.
3900 Via Oro Avenue, Long Beach, California 90810, U.S.A.
http://www.densoaftermarket.com/index.shtml
Best regards,

So I went to www.densoaftermarket.com, and it looks like they don't even list HVAC units. When I went searching, the website said "If you are looking for a part not listed here, contact your car manufacturer's local service dealer". Looks like I might need to roll on down to the local toyota. There's one down here I know people at, but they suck so I don't think I can weasel info out of them.

If at all possible, I'd like to try speaking to the car's hardware directly w/o tearing apart the factory HVAC control unit, but we'll see.

warewolf · 08-22-2005, 09:31 AM

Holy crap, batman! That digital HVAC unit has some serious brains in it!

According to toyota technical repair manuals (retrieved through alldata.com and eautorepair.net) I can perform diagnostics on my HVAC system through the HVAC control unit -- by holding down AUTO and the fresh/recirculated air buttons when turning the vehicle on. Wow. I'm beginning to think I'm severely underqualified for this :/

RoyN · 08-22-2005, 10:14 AM

maybe mastero's idea of just "emulating" a button press might be better suited for this case, as I'm afraid it will be near impossible to emulate the control unit itself...

MatrixPC · 08-22-2005, 02:44 PM

If you have one of this HVAC control
http://www.mp3car.com/vbulletin/atta...tid=5876&stc=1
Why bother going PC control?
You are pushing the button anyway unless you need the room on the dash for something else and want to hide the HVAC control

warewolf · 08-22-2005, 03:34 PM

Quote: Originally Posted by MatrixPC

If you have one of this HVAC control
http://www.mp3car.com/vbulletin/atta...tid=5876&stc=1
Why bother going PC control?
You are pushing the button anyway unless you need the room on the dash for something else and want to hide the HVAC control

I wanted to put a 16:9 aspect 7" LCD in there, but finding 7" LVDS screens is difficult. So the next greatest thing is a 4:3 aspect LCD which are much easier to come by. That'd take up the remaining space used by the HVAC control unit though. My HVAC control unit is probally the same height as the one you linked, but it's different. My roommate(s) who have a digicam are home from vacation, so I'll see if I can snap a photo of it.