System operation

GENERAL:

The automatic climate control fitted to the MEGANE is managed by four control modules. This system is called DISTRIBUTED FUNCTION. Diagnosis of the climate control, using the diagnostic tool, is performed in two ways.

The first way is module diagnosis, which allows communication with a single module (select the climate control module). The second way is function diagnosis, which allows communication with the four modules of the AIR CONDITIONING function. A description of these two diagnosis modes is given in the introduction of this repair manual.

DESCRIPTION OF AUTOMATIC CLIMATE CONTROL MODULE OPERATION:

The automatic climate control module controls the cabin ventilation, the distribution motor, the blend motor and the recirculation motor.

The automatic climate control module also monitors two sensors: the interior temperature sensor and the solar sensor.

The two sensors and the three motors are connected to the automatic climate control module by wired links. The automatic climate control module controls cabin ventilation through a modulated control signal (square wave) sent to a power module (wired link).

All other information used by the automatic climate control module or sent by it to the other modules is exchanged over the multiplexed network.

Production of cold air (cold loop) and production of warm air (heating) are controlled by the three other modules taking part in the Air Conditioning function (Cabin Central Unit, Protection and Switching Unit and engine injection module).

The main information used by the automatic climate control module is:

• +12 V parking lights,
• 0 V dimmed,
• outside temperature,
• engine coolant temperature,
• engine running status,
• engine speed,
• electrical power consumption,
• request to hold the blown air temperature.

OPERATING PARTICULARITIES:

• When the engine is off, cabin ventilation runs about 30% slower than the user request (control panel setting).
• If actuators are faulty, the climate control can no longer control them, but the request is still shown visually on the control panel: indicator lamps light up and symbols are displayed on the panel (distribution motor position, cabin blower motor speed, "AC" symbol, etc.).
• If the outside temperature sensor is faulty, the automatic climate control module lights up 5 seconds after ignition is switched on (this can help identify a problem, as the outside temperature sensor is not diagnosed by the Cabin Central Unit).

SUMMARY OF ELEMENTS CONTROLLED OR MANAGED BY THE AUTOMATIC CLIMATE CONTROL MODULE: