Rear Evaporator Replacement
Rear Evaporator Replacement
• To replace the evaporator, the rear A/C unit must be removed.
• The removed evaporator contains refrigerant oil that must be returned to the refrigerant circuit (with the new evaporator).
• For rear A/C unit - C - to be removed, the entire center console including the base support of center console - A - and insulation mat - B - installed between the base support and rear A/C unit - C - must be removed.
Removing
- Switch off the ignition.
- Remove the driver and front passenger seat.
- Remove the base support of center console - A - and insulation mat - B -.
- Remove the rear seats or rear bench seat and the rear floor covering.
- Drain the refrigerant circuit.
- Remove the rear A/C unit, refer to => [ Rear Heating and A/C Unit ] Rear Heating and A/C Unit.
- Remove the rear fresh air blower control module (J391) - D - from the rear A/C unit, refer to => [ Rear Fresh Air Blower Control Module (J391) ] Rear Fresh Air Blower Control Module (J391).
- Remove bolts - B -.
- Lift air duct - A - in the area of Rear fresh air blower (V80) - C - and remove in the - direction of the arrow -.
- Remove bolts - B -.
- Detach tabs - C - for securing the rear fresh air blower - K - to rear air distributor housing - A - on the left and right.
• The rear fresh air blower - K - is not removed from the rear A/C unit for removal and installation of the evaporator.
Do not grasp fan wheel of rear fresh air blower, force against the fan wheel or shifting the balancing weights fastened to fan wheel may cause imbalance and then problems during operation.
- Detach the lower part of air distributor housing - A - from rear A/C unit - D -.
- Remove evaporator - G - from rear A/C unit - D -.
Installing
• The removed evaporator contains refrigerant oil that must be returned to the refrigerant circuit (with the new evaporator).
• The rear fresh air blower - K - is not removed from rear A/C unit - D - for removal and installation of evaporator - G -.
• Foam seals which have not yet adapted to the sealing surfaces of rear A/C unit - D - are present on new evaporator - G -. Therefore, these seals must be pressed into rear A/C unit - D - with slightly more force.
• If the rear fresh air blower - K - and evaporator - G - are replaced at the same time, first install the v - K - in rear A/C unit - D - and then install evaporator - G -.
Installation is carried out in the reverse order while noting the following:
- Check foam seals - H - attached to replacement evaporator - G - and to the refrigerant lines for damage and proper adhesion.
- Check all foam seals and the contact surface/peripheral bevel on the lower part of rear A/C unit - A -, on evaporator - G - and on rear A/C unit - D - for damage.
• If a foam seal or a contact surface/bevel is damaged, air can escape here and noises can occur when operating the A/C system.
• If the lower part of air distributor housing - A -, the rear fresh air blower - K - and rear A/C unit - D - are not joined correctly, air can escape at the connection point thus possibly resulting in noises when the A/C system is in operation.
• If a contact surface/bevel is damaged, fill the damaged area with, for example, silicone sealant D176 001 A3. Refer to Electronic Parts Catalog.
• If a foam seal is damaged, replace it. Refer to Electronic Parts Catalog.
- Check both connections - J - at the refrigerant lines to replacement evaporator - G - for contamination and damage.
• Even slight damage (a scratch) or a little bit of dirt (a hair) can cause leakage at a connection.
- Install evaporator - G - in rear A/C unit - D -.
- Check doors - E - and - F - for proper installation in rear A/C unit - D -.
- Join the lower part of air distributor housing - A - to rear A/C unit - D -.
• Pins which are used during production as assembly aids are present on the lower part of air distributor housing - A -. Pay attention to these pins in order to avoid bending or breaking them.
• When joining the lower part of air distributor housing - A - to rear A/C unit - D -, route wire connection - L - to the rear fresh air blower - K - correctly.
- Install bolts - B - and reinstall all other removed components on rear A/C unit - D -.
- Install the rear A/C unit, refer to => [ Rear Heating and A/C Unit ] Rear Heating and A/C Unit.
- Install the removed parts in the opposite order.
- Evacuate and fill the refrigerant circuit.
- Perform the basic setting and the output diagnostic test mode of the A/C system using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• In this vehicle, the control motors are equipped with electronics. During the basic setting, a new control motor learns its position on the A/C unit and can then be activated by the rear A/C display control head (E265) / the Climatronic control module (J255) (currently all control motors are identical). Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• During the basic setting, the control motors are assigned and adapted corresponding to the switching sequence of the wiring. If this sequence does not conform with the specification, the control motors will adapt incorrectly and the door control will be wrong, refer to => [ A/C Control Motor Block Diagram ] A/C Control Motor Block Diagram.
- Install the remaining removed components.
- Check the event memory of the Climatronic control module (J255) , and the rear A/C display control head (E265) and erase any displayed malfunctions using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
- Operate the A/C system after filling the refrigerant circuit, refer to => [ A/C System Operating After Filling Refrigerant Circuit ] A/C System Operating After Filling Refrigerant Circuit.
• Note the information regarding operation of the A/C system after filling.
- Check the function of the A/C system using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.