64 50... Air Conditioner Test (R134a)

Before A/C efficiency test, satisfy following conditions: 

1. Provide a MoDiC or DIS. Safeguard electrical system integrity by checking the fault memory (no faults in the fault memory).
2. Provide a thermometer with separate gauge.
3. Perform the test in a suitable work bay with an ambient temperature between 20°C and 30°C.

Re 1:

Connect MoDiC or DIS to car and display evaporator temperature.

Re 2:

Position a thermometer with a separate gauge approx. 5 cm below the roof liner at the height of the B-pillar. Lay gauge outwards out of vehicle interior.

Re 3:

Heating up vehicle interior:

• A/C button is not  activated during heating up.
• Close all windows and doors.
• Set recirculated air mode.
• On vehicles with CID: In A/C menu (CID) in Air distribution index tab: select 100 % footwell for driver and front passenger and 100 % defrosting for driver (this applies here to driver and front passenger)
• Select air distribution mode for footwell and defrosting.
• Maximum temperature setting.
• Maximum fan stage.
• Start engine

Cool down passenger compartment: 

Turn on air conditioning compressor with "A/C button" at a vehicle interior temperature of 45 °C (measured at the head restraint).

On vehicles with MAX-AC button  : Activation of MAX-AC (= maximum cooling power)

On vehicles without MAX-AC button: 

Set maximum cooling power by means of following steps:

• Setting minimum temperature
• Blower setting maximum
• Stratification maximum cold (4 blue bars)
• Only ventilation open
• Close remaining flaps (air outlet only from center fresh air grille, left and right)

After 5 minutes measure both ventilation temperatures with a thermometer at the same time (fresh air grille center, left and right). The measured temperature must be = 16° C and the difference between right and left may not be greater than 2° C.

Draw off A/C system  if this temperature is not reached. See 64 50 009 Drawing Off, Evacuating And Filling A/C System (R134a) . Measure amount of refrigerant drawn off.

If one or both temperature specifications is not reached drain off heating and air conditioning system. Measure amount of refrigerant drawn off.