BMW 7 Series: A/C Performance Test (R 134a)
Observe the following conditions prior to the A/C performance test
1. Provision of a diagnosis system. 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 workshop area with an ambient temperature between 20ºC and 30ºC.
Re 1:
Connect diagnosis system to vehicle 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 passenger compartment.
Re 3:
Heat passenger compartment:
- "A/C button" is not activated during the heating process
- Close all windows and doors.
- Set air recirculation function.
- 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)
- Maximum temperature setting (28ºC)
- Maximum blower speed (adjust 9 pixels from 9 possible on front A/C control panel)
- Run engine at approx. 2000 RPM until operating temperature is reached, then idle speed.
Air-conditioning performance test
Turn on A/C compressor via "A/C button" at a vehicle interior temperature of 50ºC.
Vehicles with MAX-AC button ("MAX"):
- Activation of MAX-AC (= maximum cooling power)
Vehicles without MAX-AC button ("MAX"):
- Set maximum cooling power by means of following steps:
- Temperature setting = 16ºC
- Blower setting 9 pixels of 9 possible
- Stratification maximum cold (4 blue bars)
Evaporator sensor temperature must be < or = 15ºC after 3-4; minutes at approx. 2000 RPM.
DRAW OFF A/C SYSTEM if this temperature is not reached. Measure amount of refrigerant drawn off.
If drawn-off quantity does not correspond to specified fill quantity, supplement refrigerant and repeat test. See AIR CONDITIONING SYSTEM, AMOUNT OF REFRIGERANT.
If capacity is correct, continue troubleshooting by pressure measurement.
READ NEXT:
Drawing Off, Evacuating And Filling Heating And Air Conditioning
System (R 134a)
WARNING: Only persons in possession of a professional certificate
of competence for the maintenance and repair of heating and air conditioning
systems are authorized to carry out repair work on the
Instructions For Handling R 134a Refrigerant
Work on the refrigerant circuit may only be carried out by experts!
Avoid all contact with liquid or gaseous R 134a. Wear safety goggles and
gloves when working on the
refrigerant circuit.
Follow S
Leak Detection With Forming Gas
NOTE: Leak detection with forming gas replaces the leak detection that is
prohibited in
EU countries using UV.
Observe national regulations in all other countries!
IMPORTANT: Compliance with the man
SEE MORE:
Removing And Installing/replacing Left Or Right Tank Cover
Operations on right side analogous to left side shown. Use graphics in a
mirror-inverted way.
Release all screws (2).
Unscrew nut (3).
Feed out tank cover (1) towards rear above tension strut (4).
Fig. 97: Identifying Tank Cover, Screws And Nut
REMOVING AND INSTALLING/REPLACING LEFT OR RIGHT TO
Opening Adhesive Bonds
1. Opening spot-weld bonds
OPEN WELD SPOTS.
WARNING: Extract vapors and gases.
Use personal protective clothing/equipment.
Heat connecting flange with a hot-air blower. Heat components to max. 250ºC
object temperature.
Release connection flange with chisel.
Remove adhesive residue from connecti
