Another 964 heating problem - Solved :)
03-01-2012, 01:06 PM
#1
Racer
Thread Starter
Another 964 heating problem - Solved :)
I have the following problem with heating.
When start the engine and the front blower works perfect.
But after a few minutes.
Front blower stops working by itself after a few minutes from the engine start, and after the next few minutes starts again. After that is already running all the time. The problem repeats itself when the car has cooled, etc.
Same situation is when I set the temperature at approximately half the scale of the front blower stops working, but rear blower is still running (hot air is comes out).
Sometimes that when I turn left wheel on 01234 front blower turns on and immediately turns off.
Interesting is that when push button defrosting supply air works fine (hot air is comming) although not previously worked, when you turn off the button “defrosting”, the front blower again stops working.
Makes the impression that an item had to be heating or cool????
If someone had a similar problem?
Thank You for all the good tips.
Maciek
When start the engine and the front blower works perfect.
But after a few minutes.
Front blower stops working by itself after a few minutes from the engine start, and after the next few minutes starts again. After that is already running all the time. The problem repeats itself when the car has cooled, etc.
Same situation is when I set the temperature at approximately half the scale of the front blower stops working, but rear blower is still running (hot air is comes out).
Sometimes that when I turn left wheel on 01234 front blower turns on and immediately turns off.
Interesting is that when push button defrosting supply air works fine (hot air is comming) although not previously worked, when you turn off the button “defrosting”, the front blower again stops working.
Makes the impression that an item had to be heating or cool????
If someone had a similar problem?
Thank You for all the good tips.
Maciek
Last edited by Kuchar; 03-03-2012 at 05:13 AM.
03-01-2012, 03:55 PM
#4
If you have a scanner scan the HAVOC system
Yes it is the fan in the back of the CCU.
It would come up with a inside fan seized. Or take the CCU out and see if the fan works. Then see that is continues for 20 mins after you turn the car off.
A symptom of a stuck or failed sampling fan is the CCU works right for some time and then starts not to work right.
A scan would or should show any other fault codes.
Just because the fan works doesn't mean it is working correctly.
The resistor fails and the fan still runs on high speed for some time but wont run on low speed. It will aslo cause a fault code. In which case you replace the resistor.
Yes it is the fan in the back of the CCU.
It would come up with a inside fan seized. Or take the CCU out and see if the fan works. Then see that is continues for 20 mins after you turn the car off.
A symptom of a stuck or failed sampling fan is the CCU works right for some time and then starts not to work right.
A scan would or should show any other fault codes.
Just because the fan works doesn't mean it is working correctly.
The resistor fails and the fan still runs on high speed for some time but wont run on low speed. It will aslo cause a fault code. In which case you replace the resistor.
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03-01-2012, 07:08 PM
#10
Racer
Thread Starter
I was thinking about two temp sensor. Maybe they are dirty or something? And sending wrong signal. But is it difficult to take them out? I never try before.
03-02-2012, 11:56 AM
#13
Racer
Thread Starter
Laker thanks for the motivation! Sensors are attached to the housing and access is poor.
Today I changed "final stage?" mounted on the wall in the trunk.
Unfortunately, the symptoms still occur.
Today, i will try to remove the temp sensors and cleaned them. I am afraid that they are very dirty. It is 19 years old car.
Tomorrow I'll put a reserve CCU because I have a spare. I just have to soldered this BC337.
Maciek
Today I changed "final stage?" mounted on the wall in the trunk.
Unfortunately, the symptoms still occur.
Today, i will try to remove the temp sensors and cleaned them. I am afraid that they are very dirty. It is 19 years old car.
Tomorrow I'll put a reserve CCU because I have a spare. I just have to soldered this BC337.
Maciek
03-02-2012, 01:26 PM
#14
Drifting
Access is tight but only one screw each sensor and you don't have to pull out the entire unit 
The sensor tips look like that of a soldering gun. My passenger side's was broken. Code 12 for Left mixing chamber temp sensor, and 13 for Right.
The sensor tips look like that of a soldering gun. My passenger side's was broken. Code 12 for Left mixing chamber temp sensor, and 13 for Right.
Last edited by Laker; 03-02-2012 at 01:43 PM.
03-02-2012, 02:26 PM
#15
Racer
Thread Starter
I got under CCU and found that the temp sensor was covered with a big ball of dust.
I cleaned it with toothbrush. I cleaned also the potentiometers using contact cleaner.
The wife has to go somewhere. So she will test whether the heating is working correctly.
After her return i get a reliable report.
Probably it will read as follows:
I do not want to drive this car more! There is no automatic transmission, is noisy, uncomfortable, no 4x4 and I'm sitting too low!
And when I will ask: What about heating? I will hear: I forgot, driving this car is driving me crazy. Sell it! Buy white Vespa!
I cleaned it with toothbrush. I cleaned also the potentiometers using contact cleaner.
The wife has to go somewhere. So she will test whether the heating is working correctly.
After her return i get a reliable report.
Probably it will read as follows:
I do not want to drive this car more! There is no automatic transmission, is noisy, uncomfortable, no 4x4 and I'm sitting too low!
And when I will ask: What about heating? I will hear: I forgot, driving this car is driving me crazy. Sell it! Buy white Vespa!