With Expansion Valve and Reservoir (Without Regulated A/C Compressor), Checking

Checking With Expansion Valve And Reservoir (Without Regulated A/C Compressor)

Test requirements

- Radiator and condenser are clean (clean if necessary)
- The ribbed belt for the A/C compressor and alternator tensioned correctly.
- All air ducts, covers and seals are OK and properly installed
- The flaps reach their end position.
- Engine is warm
- Evaporator and heater not drawing in secondary air (at maximum fresh-air blower speed).

With engine running and A/C system set to maximum cooling output, pay attention to the following points:
- The fresh air blower is running.
- The coolant fan is running or it is switched on.
- The recirculation/fresh air flap is in the "recirculation" position.
- Ambient temperature is greater than 15 degrees C.
- The A/C Evaporator Temperature Switch E33 is installed correctly and its switch temperatures are correct.

Checking
- Switch off ignition.
- Connect pressure gauge set (A/C service station).
- Take pressure gauge readings. There are two possible results A and B.

Ambient temperature in
degrees Celsius Pressure in bar (positive pressure) in refrigerant circuit
+15 degrees C 3.9
+20 degrees C 4.7
+30 degrees C 6.7
+40 degrees C 9.1

- A- Pressure in refrigerant circuit is lower than specified in table (too little refrigerant in circuit).

- Search for leak with leak detection device.
- Pressure relief valve opened, check activation for coolant fan according to wiring diagram.

Check refrigerant pipes and hoses to see if they are bent too sharply (cross-section constrictions) or have external damage. If no malfunction is found, flush refrigerant circuit.
- Pressure in refrigerant circuit in line with table or higher:

- Start engine.
- Set A/C system to maximum cooling output.
- Open doors.
- Open vents in instrument panel.

The A/C compressor is driven by the engine via the magnetic clutch using the ribbed belt.

NOTE:
- If the A/C compressor is not driven, check A/C Clutch N25 voltage supply.
- If the voltage is OK, service magnetic clutch.

If the A/C compressor is driven, check refrigerant circuit:
- Bring engine speed up to 2000 RPM.
- Observe manometer battery:

Specified values

High-pressure side:
Increasing from pressure with engine not running to a maximum of 20 bar.

Low-pressure side:
Decreasing from pressure with engine not running down to 1.3 bar.