Author Topic: ACC not heating unless driving uphill  (Read 509 times)

gtrombone

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ACC not heating unless driving uphill
« on: 20 August 2018, 02:57:40 AM »
Hi all,

I have a new problem which I hope will be easy to diagnose:

Iíve recently noticed the heating in the car has been inconsistent. It blows fine but the air is sometimes air temp (itís winter) and sometimes heated.

I had a long drive yesterday (600km) and the air temp was below 10C all the way so I had a good chance to observe it.

What I discovered is that the air was blowing at outside air temperature UNLESS I was driving up a steep enough hill.

That is, heating was running fine uphill only.

Iíve tried a few tests with cold air (A/C) but not recently. It also seemed inconsistent.

Is there a switch or servo somewhere which would explain this problem? Which parts would I need to solve it please?

Many thanks, Gus

gtrombone

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Re: ACC not heating unless driving uphill
« Reply #1 on: 20 August 2018, 02:59:37 AM »
PS I ran the acc self diagnostic test (press auto and off simultaneously) and it just showed a ď0Ē during the testing and returned to usual operation.

sgould

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Re: ACC not heating unless driving uphill
« Reply #2 on: 20 August 2018, 09:33:57 AM »
What does the outside air temperature show up as on the dash display?  If the sensor is sending the wrong info, the aircon could be switched off automatically.  The aircon recalibration test doesn't check for temp sensors sending the wrong info. It will only notice if they are missing!i think.
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gtrombone

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Re: ACC not heating unless driving uphill
« Reply #3 on: 07 October 2018, 02:39:06 PM »
Hi,

Thanks for the suggestion sgould, there was nothing wrong with the temp reading.

The repair was a solenoid which had ceased operating. The explanation for heat working when driving up hills was that there was enough pressure in the system to force the valve open.

Many thanks!

sgould

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Re: ACC not heating unless driving uphill
« Reply #4 on: 07 October 2018, 04:05:51 PM »
Thanks for reporting back.  That was a strange fault. :o
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