Mechanics come in, ac compressor question

My compressor runs all the time when its set to climate control is defrost, even under 0c (today the temp gauge was showing -4)
the manual claims it shouldnt run when its 0c or colder outside. the ac knob is not on, and the temp is set to hot. stupid thing takes away all engine power and the fan is running all the time when the compressor is on, it drives me crazy and i dont know where to start looking, halp!
the car is vibe 2006, no lights on dash and everything runing nice and smooth.

taken from the user manual

can you see the outside temp in your car? if yes check that the temp shown is good because if the ambient temp sensor do not show the good temp a/c can stay on

Pressing the A/C button enables the PCM to request A/C compressor engagement and turn on the A/C indicator. The A/C button sends a signal to the PCM for A/C compressor engagement. The PCM will provide a ground for the A/C compressor relay enabling it to close its internal contacts to send battery voltage to the A/C compressor clutch coil. The A/C compressor diode will prevent a voltage spike, resulting from the collapse of the magnetic field of the coil, from entering the vehicle electrical system when the compressor is disengaged. Defrost and Defog mode selections will request A/C operation but not turn on the A/C indicator. The blower switch must be in any position except OFF for the A/C system to operate. The A/C system can operate regardless of the temperature control setting.

The following conditions must be met in order for the A/C compressor clutch to turn on:


Ambient air temperature above 4°C (40°F)
A/C refrigerant pressure switch parameters are met
PCM receives an A/C request from the A/C switch
Engine coolant temperature (ECT) is less than 121°C (250°F)
The engine RPM is more than 550 RPM
The throttle position is less than 100%
The PCM monitors the A/C refrigerant pressure switch signal circuit. If the PCM detects a pressure signal out of parameters, it will disable the A/C request. This switch assists in cycling the A/C compressor and prevents A/C compressor operation if system has a low refrigerant level.

The sensor information is used by the PCM to determine the following:


A/C system load on the engine
A/C system pressures
Once engaged, the compressor clutch will be disengaged for the following conditions:


Ambient air temperature is less than 4°C (40°F)
Throttle position is 100%
A/C high side pressure is more than 3140 kPa (455 psi)
A/C low side pressure is less than 196 kPa (28 psi)
Engine coolant temperature (ECT) is more than 121°C (250°F)
Engine speed is more than 5500 RPM

niko14 said:

can you see the outside temp in your car? if yes check that the temp shown is good because if the ambient temp sensor do not show the good temp a/c can stay on

Click to expand...

Yes i see it clearly showed -4, i dont know if it was really -4 bt it was freaking freezing and im sure it was under 0c

ok maybe check the list that i put out of the description and operation ( that come from alldata ( factory service manual)

Niko14 thats a great explaination , and ts proves that the stupid compressor should stop running, but it doesnt, on the legs and face no problems, but as soon as i switch to defrost and legs or defrost stupid compressor kicks in, i just tried it again with fully warm engine, ac knob off, temp set to hot , outside temp gauge shows -3c

Defrost and Defog mode selections will request A/C operation but not turn on the A/C indicator... my english is not that good but to me it mean that when you put it in defrost that send the request to active a/c ( the a/c must be use the remove the excess of humidity inside )

La plupart des chars récents avec A/C fonctionnent comme ca. Et je savais pas que le A/C était SUPPOSÉ arreter en bas de zéro degrés celsius... j'en ai jamais vu qui fonctionnaient comme ca. Nous pour les clients que sa ''dérange'' on leur enlève le relay de l'A/C, on le met dans leur coffre a gants, puis on leur remet au printemps!

RamboAE86 said:

La plupart des chars récents avec A/C fonctionnent comme ca. Et je savais pas que le A/C était SUPPOSÉ arreter en bas de zéro degrés celsius... j'en ai jamais vu qui fonctionnaient comme ca. Nous pour les clients que sa ''dérange'' on leur enlève le relay de l'A/C, on le met dans leur coffre a gants, puis on leur remet au printemps!

Click to expand...

Je sais que je peux enlever la fuse du ac ou meme si je veut me casser la tete acceder en arriere du panneau de controle de climat pour enlever un petit cable qui controlle toute cette madre, mais cest pas le but, ce que je veut savoir cest si il y un probleme a quelque part ou si le guide dutilisateur dit faux. Jutilise jamais le ac mais la commence a me taper sur les nerfs quand il fait froid et que je veut enlever la glace du windshield y run tout le temps