About cabin temperature sensor
01-31-2013, 04:16 PM
#31
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Oh..its still all apart. It looks like an old telephone switch board!
I ran the whole test outlined on 87-113 and 114
at 13c with temp selector at 18c i get 4.98 kohms..manual says 3.7 kohms
at 13c with temp selector at 30c i get 5.77 kohms..manual says 4.77kohms
difference of 790 ohms...manual says 1000.
functionally it all works fine, the difference is that the manuals test at 20'c and Im at 13c
issue now is steps 10 an 11 which appear to test the micro switch on the center vent...pic below. I tested the switch individually and it does work fine. You can see i get voltage when i am not suppose to and when i close the central vent the voltage increases .6 v or so
It may be related to an other issue i'm running down now.
My blower fan stays on LOW (perhaps even lower than LOW) even with the fan **** selected to off AND the wiring connector to the fan **** switch disconnected! Im looking at the blower resistor pack now. any ideas in that regard.
that last pic is the OHMS and temp relation on my external temp sensor to stay more on topic .
I ran the whole test outlined on 87-113 and 114
at 13c with temp selector at 18c i get 4.98 kohms..manual says 3.7 kohms
at 13c with temp selector at 30c i get 5.77 kohms..manual says 4.77kohms
difference of 790 ohms...manual says 1000.
functionally it all works fine, the difference is that the manuals test at 20'c and Im at 13c
issue now is steps 10 an 11 which appear to test the micro switch on the center vent...pic below. I tested the switch individually and it does work fine. You can see i get voltage when i am not suppose to and when i close the central vent the voltage increases .6 v or so
It may be related to an other issue i'm running down now.
My blower fan stays on LOW (perhaps even lower than LOW) even with the fan **** selected to off AND the wiring connector to the fan **** switch disconnected! Im looking at the blower resistor pack now. any ideas in that regard.that last pic is the OHMS and temp relation on my external temp sensor to stay more on topic .
01-31-2013, 04:29 PM
#32
Drifting
Your sensor string resistance readings look similar to ones I had when I was getting hot air when off the full cold microswitch. In my case the cabin tempmsensor resistance had drifted upwards out of spec, so the mixing motor "saw" the resistance it expected when demanded temp was 30C, irrespective of actual slider position. I would check out that cabin sensor.
Also Irecall doing the same voltage tests you did, and also getting some odd results that did not match those in manual, even though my hvac system was operating faultlessly (after replacing cabin sensor and its fan). Could be errors in manual?
Also Irecall doing the same voltage tests you did, and also getting some odd results that did not match those in manual, even though my hvac system was operating faultlessly (after replacing cabin sensor and its fan). Could be errors in manual?
01-31-2013, 05:04 PM
#33
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It may be related to an other issue i'm running down now. My blower fan stays on LOW (perhaps even lower than LOW) even with the fan **** selected to off AND the wiring connector to the fan **** switch disconnected! Im looking at the blower resistor pack now. any ideas in that regard.
My blower fan stays on LOW (perhaps even lower than LOW) even with the fan **** selected to off AND the wiring connector to the fan **** switch disconnected! Im looking at the blower resistor pack now. any ideas in that regard.
page 45 in the owners manual...
time to put the resistor pack back in.
....this is all SOOOooo much fun!
11-13-2016, 10:49 AM
#34
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Good afternoon dear rennlist Expert, hopefully my english will be good enough to explain my issue and understand your advises.
I am from France and actually own since 9 years a 90's GT with 346000 km that works more than perfect expect the issue bellow. MY name is Jean-Pierre and I'm 48
I have (of course because posted here
) a heating/cooling regulation issue. here are the symptoms and what I can already tell you about it.
This summer I felt that when cooling, sometime the airconditionning was operating, but not all the time (there were period of a seconds where not real that cool air was blown ).
Now in winter time, I have little "warm" air when Temp requested between 27 and 29 ° and real hot air when full request 30°, below this request, air is cold.
What I know and have done already with assistance of a friend of mine.
We checked resistence of temp request central and we have a variation of 1000 ohm as it should be, however, temp of testing condition was not 20° so not exactly from 3700 to 4700. when we check the "actuator" of the fan that is located below central console at right foot or driver (for a LHD car) it was not operating except when pushed to 30°.
We finally changed the external T° sensor and it was then (and still) operating with "inbetween" position. So I left my friend with the car and thought pb fixed.
However, Wheather is now more cold and symptoms described before still valid. Although actuator is still working on in between position (I checked under steering weel while moving the T° request).
The pb is that it is starting to move only when reaching 26-27 request , and only operating on a 20% range of what it could , and then move fully up when 30° requested.
I have doubts on the internal sensor, so I have made the folowing test, trying to cheat a bit with the sensor. I put a frozen pack (the kind that you use to keep goods cold in bags) in front of the sensor.
This has increase a bit the range of operation of the actuator up to about 40%.
So I think the inside sensor is out specification.
Did anyone of you have ever had similar experience and could provide advise / confirm my potential diagnostic ?
thanks a lot
I am from France and actually own since 9 years a 90's GT with 346000 km that works more than perfect expect the issue bellow. MY name is Jean-Pierre and I'm 48
I have (of course because posted here
) a heating/cooling regulation issue. here are the symptoms and what I can already tell you about it.This summer I felt that when cooling, sometime the airconditionning was operating, but not all the time (there were period of a seconds where not real that cool air was blown ).
Now in winter time, I have little "warm" air when Temp requested between 27 and 29 ° and real hot air when full request 30°, below this request, air is cold.
What I know and have done already with assistance of a friend of mine.
We checked resistence of temp request central and we have a variation of 1000 ohm as it should be, however, temp of testing condition was not 20° so not exactly from 3700 to 4700. when we check the "actuator" of the fan that is located below central console at right foot or driver (for a LHD car) it was not operating except when pushed to 30°.
We finally changed the external T° sensor and it was then (and still) operating with "inbetween" position. So I left my friend with the car and thought pb fixed.
However, Wheather is now more cold and symptoms described before still valid. Although actuator is still working on in between position (I checked under steering weel while moving the T° request).
The pb is that it is starting to move only when reaching 26-27 request , and only operating on a 20% range of what it could , and then move fully up when 30° requested.
I have doubts on the internal sensor, so I have made the folowing test, trying to cheat a bit with the sensor. I put a frozen pack (the kind that you use to keep goods cold in bags) in front of the sensor.
This has increase a bit the range of operation of the actuator up to about 40%.
So I think the inside sensor is out specification.
Did anyone of you have ever had similar experience and could provide advise / confirm my potential diagnostic ?
thanks a lot
