Air condition it's not working

HVAC Compressor Controls Circuit Description
The operation of the A/C compressor clutch is controlled by the body control module (BCM) and powertrain control module (PCM). The BCM receives an a/c request signal from the heater a/c control assembly through circuit 66. The BCM then sends a class 2 serial data message to the PCM through circuit 1807. Power for the a/c compressor clutch relay is supplied by the A/C BFC fuse and circuit 439. When the PCM receives an a/c request message from the BCM, the PCM grounds circuit 459 allowing the a/c compressor clutch relay to engage. Ground for the a/c compressor clutch is supplied through circuit 450.
Do you know what a class 2 serial data message is ?
Class 2 data is a high speed data transmission. In order to control serial data line traffic, class 2 uses the peer to peer method along with message arbitration in order to manage the data line traffic. The class 2 data line includes the following control modules:
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The body control module (BCM)

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The electronic brake control module (EBCM)

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The powertrain control module (PCM)

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The sensing and diagnostic module (SDM)

You need a factory scan tool to diagnosis , it's the only way to see if transmission is sent an received !
The intake air temperature (IAT) sensor is a thermistor which measures the temperature of the air entering the engine. The Powertrain Control Module (PCM) applies 5.0 volts through a pull up resistor. When the intake air is cold, the sensor resistance is high and the PCM will monitor a high signal voltage on the IAT sensor signal circuit. As the intake air warm, the sensor resistance becomes lower causing the PCM to monitor a lower voltage. If the PCM detects an excessively high IAT sensor signal voltage (low temperature indicated), DTC P0113 will set.
Test the signal circuit of the IAT sensor for a short to voltage. Refer to Wiring Repairs in Wiring Systems.

Do you ko

body control module is a generic term for an electronic control unit responsible for monitoring and controlling various electronic accessories in a vehicle's body. Typically in a car the BCM controls the power windows, power mirrors, air conditioning, immobilizer system, central locking, etc. The BCM communicates with other on-board computers via the car's vehicle bus, and its main application is controlling load drivers - actuating relays that in turn perform actions in the vehicle such as locking the doors or dimming the salon overhead lamp. Check the fuses the wiring going to the dash. even some times banging on it corrects the problem

The lite blue orange wire grounds the ac clutch relay. The engine computer is supposed to do this IF conditions are right for the ac to function. There could be a problem with one of the freon pressure sensors or the AC control module. If you are not getting a normal level of cold air from the vents, and the mechanical system is functioning correctly, the problem may be the ac control module. There may be blend doors that are not open or closed as they should be.
This is normally beyond most DIY people, so info is not available in over the counter repair books. A shop that knows how to work on electronic ac systems and a shop manual may be needed.

So the mechanic did all the necessary testing ?

If not then is is only a guess,you change nothing

Common Sense

The idle is not controlled by the body module
as the name implies
Body is windows,sun roof,air conditioning,fan control
radio etc not the motor

Great advice--- right?

Hi Jose:
The first place to start is to have Ride Control Module scanned for trouble codes, this requires a high end scan tool. Most common problem is the air compressor in the rear or a height sensor. Here is how the system works.

Automatic Level Control Description and Operation
The RTD system is bi-state real time damping system. The Suspension Control module controls the suspension damper solenoids and suspension position sensors, along with parts of the automatic level control (ALC) system and electronic variable orifice (EVO) power steering system.

The Automatic Level Control system consists of the following:
• Suspension Control Module
• Compressor/Leveling Module
- Air Pressure Sensor
- Exhaust Solenoid
• Compressor Motor Relay

The objective of the Automatic Level Control System is to provide constant ride height at all load conditions. The Suspension Control module monitors body-to-wheel height, and vehicle speed.

The Suspension Control module will use the rear body-to-wheel displacements and vehicle speed inputs to keep the rear trim height of the vehicle at its desired level.

The electronic suspension control (ESC) system is bi-state real time damping system. The ESC module controls the suspension damper solenoids and suspension position sensors, along with parts of the automatic level control (ALC) system, if 1500 series.

The ESC system consists of the following:
• The ESC module
• The compressor/leveling module, if 1500 series
- The air pressure sensor, if 1500 series
- The exhaust solenoid, if 1500 series
• The compressor motor relay, if 1500 series
• The steering handwheel speed/position sensor
• The suspension damper solenoids
• The suspension position sensors

Hope this helps; also keep in mind that your feedback is important and I'll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using Fixya, and have a nice day.

if the low side tube is cold while the compressor is working the problem will be on air door module, or one piece of hose from intake manifold go to recirculation door is dis connected, but if he compressor is not working, there is only two reason, even the refrigerant pressure is too high or too low, if low a leak on your system, if too high overcharge or clogged expansion valve or the condenser, if refrigrant is i the right pressure and compressor is not working, check the supply on main switch, ambient temperature sensor, refrigrant pressure sensor and the high pressure sensor, if all ok,. replace compressor

Do you hear the air conditioning compressor switch on (with the engine running) when you turn on the air conditioning from inside the car. Get a friend to turn on and off the air conditioning while you listen with the hood open engine running you should hear a clicking sound on and off each time the a/c is cycled on and off or the a/c clutch is not locking up the compressor. This may be due to many things (bad clutch, bad compressor, no power to controls or compressor clutch) but it could be a sign of low charge the system has a low pressure switch which prevents the system from being energized if the system has low refrigerant charge. By protecting itself it prevent catastrophic failure of the compressor and ensuing damage to the rest of the a/c system if the system looses it charge. You will need to have the system checked out by someone experienced in air conditioning work who will attach pressure gauges to your car and see if the refrigerant pressures are OK. The system naturally looses some refrigerant over time but if the system constantly looses charge then it has a leak that must be investigated and repaired before just recharging the system

Ok if your air conditioning system has lost the freon leak and the compressor does not start even if you have well I recommend the fuses check if you have full charge of freon in the system and then wanted another cause. Thanks

If everything else is working, the compressor and the air bags are good, and the lines are ok, then you might have a bad leveling switch. That what actually controls the compressor.

You were not clear, but I assume the compressor runs OK. If not, troubleshoot the electrical to the compressor. Did you replace the orifice tube while it was discharged for service? If not, then check the pressures. If low side pressure is high the tube might be plugged, especially if you truly had a bad compressor. In a properly working system the line should be cold on the evaporator side of the orifice tube when properly charged. If compressor runs, system properly charged and that line is warm then suspect a plugged tube.