A/C compressor question
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Race Director
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A/C compressor question
Can anyone tell if you are using the A/C and gun the engine, does the car turn the compressor off immediately to give you full power/torque?
Safety Car
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From: Monument CO
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Le Mans Master
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From: Chandler Arizona
Where is it stated in the manual? I thought this also until I looked at HPtuners and it shows that the A/C compressor does not turn off. There have been other threads concerning this and the conclusion was it does not turn off.
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Team Owner
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From: McKinney TX
St. Jude Donor '21-'22-'23-'24
I don't think it will shut off automatically if you hit the throttle hard under any circumstances.
Pro
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From: Antelope CA
Funny, this was the turbo switch in our old 4 bangers 
just switch off the A/C for passing power 
I thought I heard here that when the coolant got too hot, it shut down the compressor, hadn't heard the WOT until now. Who really knows
just switch off the A/C for passing power I thought I heard here that when the coolant got too hot, it shut down the compressor, hadn't heard the WOT until now. Who really knows
Le Mans Master
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From: Hope, Arkansas - '07 LMB Coupe
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The 2007 service manual states on page 10-191 under the topic Heating and A/C Operation:
Once engaged, the compressor clutch will be disengaged for the following conditions:
Team Owner
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St. Jude Donor '21-'22-'23-'24
Very good. I'd always heard it did, but couldn't find it in the owner's manual.
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From: Chandler Arizona
http://www.hptuners.com/forum/showth...2Fc+compressor
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St. Jude Donor '05-'06-'07-'10
This is correct. Here is the excerpt from the service manual. I've highlighted in bold the relevant text.
The A/C system is engaged by selecting any switch on the HVAC control module except the, A/C OFF switch. The A/C switch will illuminate, A/C OFF, when the A/C switch is selected. The HVAC control module sends a class 2 A/C request message to the body control module (BCM) for A/C compressor clutch operation. The BCM must communicate with the ECM in order for the A/C clutch to be engaged. The HVAC system uses a compact variable swash plate compressor. The following conditions must be met in order for the ECM to turn on the compressor clutch from the HVAC control module request:
BCM will allow A/C operation if the following limits are within normal operating range
A/C line pressure
A/C refrigerant low temperature
Ambient temperature
Engine coolant temperature
Battery voltage
HVAC control module
OAT temperature more than 1.5°C (35°F)
Control module operating range 9 and 16 volts
ECM
Engine coolant temperature (ECT) is less than 128°C (262°F)
Engine RPM is more than 0 RPM
A/C pressure is between 2850 kPa (413 psi) and 204 kPa (30 psi).
Once engaged, the compressor clutch will be disengaged for the following conditions:
Throttle position is 100%
A/C pressure is more than 2850 kPa (413 psi)
A/C pressure is less than 204 kPa (30 psi)
Engine coolant temperature (ECT) is more than 128°C (262°F)
BCM will allow A/C operation if the following limits are within normal operating range
A/C line pressure
A/C refrigerant low temperature
Ambient temperature
Engine coolant temperature
Battery voltage
HVAC control module
OAT temperature more than 1.5°C (35°F)
Control module operating range 9 and 16 volts
ECM
Engine coolant temperature (ECT) is less than 128°C (262°F)
Engine RPM is more than 0 RPM
A/C pressure is between 2850 kPa (413 psi) and 204 kPa (30 psi).
Once engaged, the compressor clutch will be disengaged for the following conditions:
Throttle position is 100%
A/C pressure is more than 2850 kPa (413 psi)
A/C pressure is less than 204 kPa (30 psi)
Engine coolant temperature (ECT) is more than 128°C (262°F)
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