08 equinox ac fan blower erratic
September 6th, 2018, 6:42 AM
#1
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08 equinox ac fan blower erratic
My 08 NOX has competed 160k. I noticed During the recent spell of hot weather that the ac blower speed was very erratic. Ie the. Flow of air speed kept varying. Using obd I noticed that the ac high side pressure varies between 130-260 psi. The air was cold though. Is my compressor giving way?
September 6th, 2018, 2:01 PM
#2
My 08 NOX has competed 160k. I noticed During the recent spell of hot weather that the ac blower speed was very erratic. Ie the. Flow of air speed kept varying. Using obd I noticed that the ac high side pressure varies between 130-260 psi. The air was cold though. Is my compressor giving way?
There are two things that will dramatically impact the perceived blower motor speed and air output. The first is that the climate control unit will sometimes automatically switch between recirculation and vent modes when the A/C is running. This is supposed to help regulate A/C system pressure when necessary and is perfectly normal, but obviously the blower motor is much louder when recirculation mode is selected. The other factor is Electrical Power Management (EPM). In short, the alternator's output voltage is regulated by a computer to help optimize battery charging. As a result, when output voltage is low, blower motor speed decreases. I've monitored System Voltage on the DIC when this occurs and blower motor speed noticeably drops when the voltage drops below about 13.2 volts. I've seen voltage as low as 12.6V while driving on long trips which is normal operation. You can override EPM by manually turning on your headlights. This will keep output voltage around 13.9-14.1 volts.
It is also normal for A/C compressor to cycle on/off. The computer monitors refrigerant pressure and temperature at the evaporator core, and cycles the compressor accordingly.
September 6th, 2018, 4:49 PM
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That was a clear and concise response. Thanks.
You metioned that the system overrides internal circulation based on demand. This probably explains outside odours in recirculating mode.
You metioned that the system overrides internal circulation based on demand. This probably explains outside odours in recirculating mode.
September 6th, 2018, 5:15 PM
#4
If you are smelling any odors at all, you should check your cabin air filter.