AC compressor cycles even when HVAC system is off
05-21-2017, 06:27 PM
#1
What am I doing here?
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Join Date: Mar 2006
Location: 2017 Miata RF Launch Edition
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AC compressor cycles even when HVAC system is off
Here's one I noticed a while ago but only recently started chasing it down.
Car: 2005 6spd Base w/sport package (manual HVAC controls).
Symptoms:
I can hear a click inside and outside the car and the MAF rate will jump about 0.5 g/s. 5-10 seconds later, another click and the MAF rate drops back down. 5-10 seconds later, another click, MAF rate jumps again. Repeat.
It happens when the AC is on or off, including when the entire HVAC system is off.
I disconnected the wire going to the AC compressor and it stopped but this isn't a long term solution.
Anyone else run into this one before?
Car: 2005 6spd Base w/sport package (manual HVAC controls).
Symptoms:
I can hear a click inside and outside the car and the MAF rate will jump about 0.5 g/s. 5-10 seconds later, another click and the MAF rate drops back down. 5-10 seconds later, another click, MAF rate jumps again. Repeat.
It happens when the AC is on or off, including when the entire HVAC system is off.
I disconnected the wire going to the AC compressor and it stopped but this isn't a long term solution.
Anyone else run into this one before?
Last edited by NotAPreppie; 05-22-2017 at 08:00 AM.
05-21-2017, 10:25 PM
#4
I noticed same. I also believe, as above, that it turns on in any mode that includes window vents. So if you put it to just face or just feet, it shouldn't cycle. This makes some sense, you want dry, conditioned air, not wet regular air for your windows. I suspect this is as designed. The fact that it cycles even with the hvac fan at 0 might just be a programming oversight.
05-22-2017, 07:58 AM
#6
What am I doing here?
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The AC compressor is definitely cycling on/off regardless of any HVAC settings (AC button on/off, any blower output selection from 0 to max, any vent selection). It stops when I unplug the wiring harness from the AC compressor.