Toyota Yaris Forums - Ultimate Yaris Enthusiast Site
 

 


 
Go Back   Toyota Yaris Forums - Ultimate Yaris Enthusiast Site > Technical Forums > DIY / Maintenance / Service
  The Tire Rack

Reply
 
Thread Tools Display Modes
Old 12-27-2014, 06:52 PM   #1
dj92
Embracing Curves
 
dj92's Avatar
 
Drives: '14 Prius Executive
Join Date: Aug 2013
Location: mid-western Germany
Posts: 256
Automatic A/C: Ambient sensor airflow?

Hi,
I'm gathering parts to give my HB an automatic A/C, sadly some things are a bit confusing.
As I have no service manuals, I have had a look at an EPC drawing which showed an air duct going from the ambient sensor to the upper section of the air box - some cm behind the flaps.
However, there's a piece of plastic not closer specified on the drawing which connects duct and air box.
As the air box is quite expensive here, I want to get away by simply connecting the sensor and the air box with a small tube, but two questions arise:

1)What is this sensor supposed to measure?
If it's the mixed air being about to enter the cabin, it seems legit.
If it's the actual cabin air temperature, wouldn't it be better to connect it to a small pc fan or the intake side of the blower?

2)Is that piece of plastic some kind of valve?
__________________
I drive, therefore I am.
dj92 is offline   Reply With Quote
Old 12-27-2014, 07:07 PM   #2
CTScott
ULTIMATE
 
CTScott's Avatar
 
Drives: 09 5dr LB, 2x 08 3dr LB
Join Date: Oct 2008
Location: USA, CT
Posts: 13,460
The ambient temp sensor measures the cabin air temp. I believe that the tube simply creates a suction (venturi effect) so that the ambient sensor gets air from the cabin, rather than from the dash.

And, that piece is just a flexible plastic tube.

I have also done a couple of the conversions, so I can help if you have any issues.
__________________
CTScott is offline   Reply With Quote
Old 12-27-2014, 07:18 PM   #3
dj92
Embracing Curves
 
dj92's Avatar
 
Drives: '14 Prius Executive
Join Date: Aug 2013
Location: mid-western Germany
Posts: 256
Thanks for your answer

Quote:
Originally Posted by CTScott View Post
I have also done a couple of the conversions, so I can help if you have any issues.
OK, another issue is the solar sensor - also pretty expensive here (80€ or so) and hard to get, so I feel tempted to test my electronic skills
It is drawn like a diode, so I would assume that it is a photo diode.
Have you made any experiments with usual photo diodes (dark vs. light current etc.) or did you always use the original sensor?
__________________
I drive, therefore I am.
dj92 is offline   Reply With Quote
Old 12-27-2014, 07:58 PM   #4
CTScott
ULTIMATE
 
CTScott's Avatar
 
Drives: 09 5dr LB, 2x 08 3dr LB
Join Date: Oct 2008
Location: USA, CT
Posts: 13,460
Quote:
Originally Posted by dj92 View Post
Thanks for your answer



OK, another issue is the solar sensor - also pretty expensive here (80€ or so) and hard to get, so I feel tempted to test my electronic skills
It is drawn like a diode, so I would assume that it is a photo diode.
Have you made any experiments with usual photo diodes (dark vs. light current etc.) or did you always use the original sensor?
The OEM sensors are used on many other Toyotas, so they can be found inexpensively. They are just photo diodes, but I didn't test the characteristics. I may have on hand. If I do I will check it out shortly.

I checked and do not have one, but the service manual for the Prius (which uses the same sensor) confirms it is a photo diode. The only specs it lists is that the resistance of the photo diode will be an open circuit in dark and not an open circuit in light.
__________________

Last edited by CTScott; 12-27-2014 at 10:07 PM.
CTScott is offline   Reply With Quote
Old 01-02-2015, 10:00 AM   #5
dj92
Embracing Curves
 
dj92's Avatar
 
Drives: '14 Prius Executive
Join Date: Aug 2013
Location: mid-western Germany
Posts: 256
Now I have got the parts and successfully soldered white LEDs into the control assembly, but I'm already running into problems.

Following the wiring diagram, I thought the servos to have included some LIN electronics or the like, so it could be on a 3 wire bus.

Instead, each one has 5 pins, 3 of them lead to some kind of rotary encoder and the other ones lead directly to the motor.

Before I start analyzing the PCB:
Do you have any hints to which pins these servos connect to?
Sadly, I was not able to get the connectors or even a wiring harness.
__________________
I drive, therefore I am.
dj92 is offline   Reply With Quote
Old 01-02-2015, 10:58 PM   #6
CTScott
ULTIMATE
 
CTScott's Avatar
 
Drives: 09 5dr LB, 2x 08 3dr LB
Join Date: Oct 2008
Location: USA, CT
Posts: 13,460
Quote:
Originally Posted by dj92 View Post
Now I have got the parts and successfully soldered white LEDs into the control assembly, but I'm already running into problems.

Following the wiring diagram, I thought the servos to have included some LIN electronics or the like, so it could be on a 3 wire bus.

Instead, each one has 5 pins, 3 of them lead to some kind of rotary encoder and the other ones lead directly to the motor.

Before I start analyzing the PCB:
Do you have any hints to which pins these servos connect to?
Sadly, I was not able to get the connectors or even a wiring harness.
I have always gotten them with the harness between the servos and the ECU, so I have never had to worry about that pinout. Let me see what I can find, as the service manual does not even show that info.
__________________
CTScott is offline   Reply With Quote
Old 01-04-2015, 02:06 PM   #7
dj92
Embracing Curves
 
dj92's Avatar
 
Drives: '14 Prius Executive
Join Date: Aug 2013
Location: mid-western Germany
Posts: 256
I have had a look at some drawings and have come to the conclusion that the servo controllers are a part of the rather small servo harness.
I am not a 100% sure, but it seems to cost about 160€.
That's a lot, however, the alternative would be building 3 servo controllers which would be cost effective, but take a bunch of weeks.
The even bigger problem is, the 4800 baud serial data on the bus pin does not change as I e.g. change where the air goes out according to the display.
Possibly, this is because the A/C is missing the other devices on the can bus, but the weather ATM is too cold for me to spend some hours outside in my car, so I hesitate to pull the original A/Cs fuses and hook it up to the bus.
Techstream requires the ECU to be present on the bus, so I can not do anything with it up to now.

My automatic A/C came from a european TS which is almost entirely JDM and has an air ionizer which I did not find on any wiring diagram - did you have any mysterious wires on the connectors you bought?
__________________
I drive, therefore I am.

Last edited by dj92; 01-04-2015 at 05:41 PM.
dj92 is offline   Reply With Quote
Old 01-04-2015, 09:08 PM   #8
CTScott
ULTIMATE
 
CTScott's Avatar
 
Drives: 09 5dr LB, 2x 08 3dr LB
Join Date: Oct 2008
Location: USA, CT
Posts: 13,460
Quote:
Originally Posted by dj92 View Post
I have had a look at some drawings and have come to the conclusion that the servo controllers are a part of the rather small servo harness.
I am not a 100% sure, but it seems to cost about 160€.
That's a lot, however, the alternative would be building 3 servo controllers which would be cost effective, but take a bunch of weeks.
The even bigger problem is, the 4800 baud serial data on the bus pin does not change as I e.g. change where the air goes out according to the display.
Possibly, this is because the A/C is missing the other devices on the can bus, but the weather ATM is too cold for me to spend some hours outside in my car, so I hesitate to pull the original A/Cs fuses and hook it up to the bus.
Techstream requires the ECU to be present on the bus, so I can not do anything with it up to now.

My automatic A/C came from a european TS which is almostentirely JDM and has an air ionizer which I did not find on any wiring diagram - did you have any mysterious wires on the connectors you bought?
Everything made sense wiring-wise on what I had. I never had one with the ionizer.
__________________
CTScott is offline   Reply With Quote
Old 01-05-2015, 07:43 PM   #9
dj92
Embracing Curves
 
dj92's Avatar
 
Drives: '14 Prius Executive
Join Date: Aug 2013
Location: mid-western Germany
Posts: 256
I poked into it with Techstream and found out that it in fact misses the servo controllers - this single-wire bus is bi-directional.
You don't have only the harness with the controllers inside to sell, do you?
__________________
I drive, therefore I am.
dj92 is offline   Reply With Quote
Old 01-09-2015, 03:53 PM   #10
Astroman
Modded Moderator
 
Astroman's Avatar
 
Drives: 07 Toyota Yaris, 71 Galaxie
Join Date: Mar 2007
Location: Wenatchee, WA
Posts: 3,670
This was posted in the wrong section of the forum, moved it to the correct one.
Astroman is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
JDM Automatic A/C Conversion Demonstration CTScott DIY / Maintenance / Service 7 04-02-2022 05:44 PM
A/C Not Blowing Cold Air...among other things yarisitis DIY / Maintenance / Service 38 07-28-2016 04:00 PM
DIY: Unlink A/C from Defroster stran DIY / Maintenance / Service 46 01-19-2015 09:17 PM
A/C Clutch Compressor question tmontague DIY / Maintenance / Service 3 05-11-2014 07:57 AM
Problem help MickZEL DIY / Maintenance / Service 38 08-01-2011 02:52 PM


All times are GMT -4. The time now is 01:06 AM.




YarisWorld
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.