AC only works when moving
06-29-2019, 11:55 AM
#1
AC only works when moving
Hey guys,
I've got a strange issue. The AC in our 958 works, but only blows cold when we're driving. If we stand still, it blows but is no longer cold. The car was hit in the front in the past, so everything is possible.
Any ideas? I can't find a specific fuse for the AC fan (if there even is a separate one?).
I've got a strange issue. The AC in our 958 works, but only blows cold when we're driving. If we stand still, it blows but is no longer cold. The car was hit in the front in the past, so everything is possible.
Any ideas? I can't find a specific fuse for the AC fan (if there even is a separate one?).
06-29-2019, 02:38 PM
#2
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Your AC condensor fan probably isn't working. So the condensor overheats when you're stationary and the system shuts off the compressor to prevent damage. It's the BIG fan. And there is a fuse for it - might be in the fuse-block above the battery. FWIW - that fan should be running whenever the AC is on.
06-29-2019, 07:19 PM
#3
Your AC condensor fan probably isn't working. So the condensor overheats when you're stationary and the system shuts off the compressor to prevent damage. It's the BIG fan. And there is a fuse for it - might be in the fuse-block above the battery. FWIW - that fan should be running whenever the AC is on.
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Dsandler (06-30-2019)
06-29-2019, 07:39 PM
#4
I had the same problem with my college beater. It was “260 air.” Two windows down, sixty miles an hour.
Wouldn’t hurt to open the hood and have someone turn on/off AC to see if compressor clutch can be heard engaging. I would recommend doing that while vehicle stationary. Dellenberger’s probably right though.
Wouldn’t hurt to open the hood and have someone turn on/off AC to see if compressor clutch can be heard engaging. I would recommend doing that while vehicle stationary. Dellenberger’s probably right though.
06-29-2019, 09:22 PM
#5
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Just went through AllData - the 958 has a single fan used for engine cooling and HVAC use. I suspect it runs sooner when the HVAC is used. Do make sure it turns on when the HVAC is turned on.
This is a situation where it would be useful to have a decent diagnostics tool that can connect to the HVAC controller. I know iCarScan can read system pressures at several points in the system. If the amount of gas in the system was low - it might cause no AC when the vehicle is stationary and RPM is low.
This is a situation where it would be useful to have a decent diagnostics tool that can connect to the HVAC controller. I know iCarScan can read system pressures at several points in the system. If the amount of gas in the system was low - it might cause no AC when the vehicle is stationary and RPM is low.
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Macaero (09-22-2020)
06-30-2019, 05:35 AM
#6
Just went through AllData - the 958 has a single fan used for engine cooling and HVAC use. I suspect it runs sooner when the HVAC is used. Do make sure it turns on when the HVAC is turned on.
This is a situation where it would be useful to have a decent diagnostics tool that can connect to the HVAC controller. I know iCarScan can read system pressures at several points in the system. If the amount of gas in the system was low - it might cause no AC when the vehicle is stationary and RPM is low.
This is a situation where it would be useful to have a decent diagnostics tool that can connect to the HVAC controller. I know iCarScan can read system pressures at several points in the system. If the amount of gas in the system was low - it might cause no AC when the vehicle is stationary and RPM is low.
Do you know of any resource I could use to look up the correct part number for the engine fan I need based on VIN? I ask due to the accident I mentioned - I can see the part number on the fan body but I have to assume the possibility that the wrong fan may have been used.
Last edited by Konrad KP; 06-30-2019 at 06:23 AM.
07-02-2019, 10:11 AM
#7
Burning Brakes
For sure the fan has (at least) 2 speeds.. When the engine is running with the A/C on, you can feel a breeze with the hood up and see the fan spinning. When you use the "Max A/C" button, the fan goes into high speed and even with the hood shut, it's clearly audible.
Are you getting both speeds?
(I suppose given Porsche's over-engineering of everything else that the fan could be PWM controlled and actually be variable with numerous speeds, but I've noticed 2 speeds thus far.)
Are you getting both speeds?
(I suppose given Porsche's over-engineering of everything else that the fan could be PWM controlled and actually be variable with numerous speeds, but I've noticed 2 speeds thus far.)
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07-02-2019, 10:43 AM
#8
For sure the fan has (at least) 2 speeds.. When the engine is running with the A/C on, you can feel a breeze with the hood up and see the fan spinning. When you use the "Max A/C" button, the fan goes into high speed and even with the hood shut, it's clearly audible.
Are you getting both speeds?
(I suppose given Porsche's over-engineering of everything else that the fan could be PWM controlled and actually be variable with numerous speeds, but I've noticed 2 speeds thus far.)
Are you getting both speeds?
(I suppose given Porsche's over-engineering of everything else that the fan could be PWM controlled and actually be variable with numerous speeds, but I've noticed 2 speeds thus far.)
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deilenberger (07-02-2019)
07-02-2019, 01:55 PM
#9
07-02-2019, 02:21 PM
#10
07-02-2019, 03:53 PM
#13
Burning Brakes
07-07-2019, 04:34 PM
#15
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I guess you didn't read where he said "The system isn't low on gas, it was recharged last summer and even then it didn't work."?? Or where he found the fan NEVER runs? The gas (which is no longer freon) wouldn't suddenly fill up all by itself when the Cayenne was at speed..