Heater And A/C Unit, Removing And Installing: Removing
- When removing the bolts, make note of the lengths and allocation.
- All cable ties and other wiring harness fasteners released or cut open when removing the heater and A/C units are to be re-attached in same position on installation.
- Immediately seal off any open line connections and connection points with clean plugs, for example, taken from the Engine Bung Set:VAS 6122 .
Vehicles with High-Voltage System
-- Switch off (deactivate) the "parking air conditioner".Refer to Owner's Manual.
-- Switch the ignition on.
-- Bleed the coolant for the engine coolant circuit. Refer to BLEED COOLING SYSTEM - 2.0 or COOLANT, ADDING AND BLEEDING COOLING SYSTEM, VEHICLE WITH HIGH-VOLTAGE SYSTEM, HIGH-VOLTAGE SYSTEM COOLANT CIRCUIT - 3.0 .
-- Vehicles with Heat Pump Function, initiate the A/C system basic setting through the Thermal Management Control Module -J1024- and open the power-activated valves through the stored routine Extract, evacuate and fill the refrigerant circuit using the Vehicle Diagnostic Tester .
-- Switch off the ignition.
Continuation for all vehicles
-- Discharge the refrigerant circuit. Refer to Refrigerant Circuit or A/C SERVICE STATION, USING .
-- Remove the plenum chamber bulkhead. Refer to PLENUM CHAMBER BULKHEAD, REMOVING AND INSTALLING .
The cooling system is under pressure when the engine is warm. There is a risk of scalding due to hot steam and hot coolant.
Scalding the skin and other parts of the body is possible.
- Wear safety gloves.
- Wear protective eyewear.
- Reduce the pressure by covering the coolant expansion tank cap with a cloth and carefully opening it.
-- Carefully open the coolant expansion tank cap -A- (do not completely remove).
- There are different versions of the coolant expansion tank and with different allocations in the engine compartment. Refer to BLEED COOLING SYSTEM - 2.0 or COOLANT, ADDING AND BLEEDING COOLING SYSTEM, VEHICLE WITH HIGH-VOLTAGE SYSTEM, HIGH-VOLTAGE SYSTEM COOLANT CIRCUIT - 3.0 .
-- Label the layout of the coolant hoses at the connections to the heater core -A- (supply from the Coolant Recirculation Pump -V50-)and -B- (return to the engine).
-- Clamp off the coolant hoses -A and B- using Hose Clamps - Up To 25mm:3094 -E-.
-- Cover the area beneath connections for coolant hoses -A and B-, or example with absorbent paper.
-- Place a small container under the connections for coolant hoses -A and B-.
-- Remove the coolant hoses -A and B- from the connections to the heater and A/C unit heater core.
-- Insert one section each of hose -A and B- on to both connections to heater core.
-- Place the container -B- under the other end of the hose -C-.
-- Using a compressed air gun -D-, arefully blow coolant out of the heater core against the normal flow direction of the coolant) via the hose -A- into a container -B-.
-- Disconnect the refrigerant lines -A and C- from the front expansion valve -D- and put aside (do not remove). Refer to FRONT EXPANSION VALVE, REMOVING AND INSTALLING .
-- Loosen the grommet with the support ring -D- from the plenum chamber rear wall toward the passenger compartment (it is removed and installed with the heater and A/C unit).
-- Vehicles with a "Mid","Mix" or "High" A/C system, remove the rear heater and A/C unit. Refer to HEATER AND A/C UNIT, REMOVING AND INSTALLING, "High" A/C SYSTEM, PR NUMBER 9AH/ 9AQ .
-- Remove the instrument panel crossmember. Refer to INSTRUMENT PANEL CROSSMEMBER, REMOVING AND INSTALLING .
-- Vehicles with a "Low" A/C system, remove the rear air duct. Refer to AIR DUCTS AND VENTS IN REAR VEHICLE INTERIOR, PR NUMBER 9AD .
-- On vehicles with Auxiliary Heater Control Module -J604- with Auxiliary Heater Heating Element -Z35-, nterrupt the power supply to the Auxiliary Heater Heating Element -Z35- by pulling the corresponding fuse. Refer to Wiring Diagram.
-- Release and disconnect the connector -A- and remove from the connections -C- (plus) and -B-.
-- Pull the carpet in the area of the center tunnel slightly to the side.
-- Unclip the support for the A/C unit -1- downward in the direction of -arrow A- from the heater and A/C unit -2- and remove in the direction of -arrow B-.
-- Remove the condensation water drains -A- from the connections -B- on the heater and A/C unit.
- The "A/C system" wiring harness is removed with the heater and A/C unit.
-- Cover the floor covering in the area of the center tunnel with a sturdy mat.
-- Free up the wiring harness -F-.
-- Remove the grommet -E- for the coolant pipes to the heat exchanger and grommet -D- for the expansion valve from the openings in the rear wall of the plenum chamber and carefully detach the heater and A/C unit -C- (so that no components are damaged by any still attached connections) slightly from the vehicle and remove it in the direction of the front passenger footwell.