Housing Assembly HVAC: Service and Repair
WM 851519 Removing and installing heater/air-conditioning unit
Preliminary work
1. Drain coolant. -> 193817 Draining and filling coolant (includes bleeding) - section on "Draining and filling" Service and Repair
2. Drain refrigerant. -> 870317 Draining and filling refrigerant - section on "Draining" Service and Repair
3. Remove dashboard bracket. -> 701219 Removing and installing dashboard bracket - section on "Removing"
4. Remove the condenser/evaporator line and compressor/evaporator line at the expansion valve and close the connections. -> 877019 Removing and installing expansion valve - section on "Removing" 877019 Removing and installing expansion valve
Removing heater/air-conditioning unit
Information
The heat exchanger connection must be closed off using suitable stoppers once the cooling water hoses have been removed.
Information
- Line the driver's footwell with very absorbent material.
Installation position of heater/air-conditioning unit
1. Unscrew two fastening screws -1- on the cover on the coolant lines.
Cover on coolant lines
2. Remove cover for coolant lines.
3. Release electric plug connection for the servo motors at the heater/air-conditioning unit -a- and disconnect it -arrow-.
Pulling off connector for servo motors
4. Pull the retaining clips -2- on the coolant supply line and return line downwards -arrow A-.
Pulling off retaining clips on coolant lines
5. Pull the interior carpet away from the coolant lines and place a suitable collecting container under the lines.
6. Carefully pull the coolant lines out of the heat exchanger -arrow B- and drain the coolant into the collecting container.
7. Release the clamp -3- and pull the water drain hose off the heater/air-conditioning unit.
Pulling off water drain hose
8. Disconnect the centre air vents for the footwell and slide them onto the heater/air-conditioning unit. -> 805519 Removing and installing front footwell outlet vent - section on "Removing" 805519 Removing and installing front footwell outlet vents
9. Unclip the main wire harness and cable duct at the heater/air-conditioning unit at the left and right -arrows-.
Unclipping main wire harness
10. Grasp the heater/air-conditioning unit at the left and right, pull it backwards and remove completely.
Installing heater/air-conditioning unit
Information
Before the heater/air-conditioning unit is installed again, the following points must be checked:
- Check the water drainage hose for any cracks, deformities and other damage.
Water drainage hose
- Check on the body for damage to both mounts (stars) for the heater/air-conditioning unit. The stars must be able to turn for installation.
Checking the mounts (stars) for the heater/air-conditioning unit
- Both mounts for the stars on the heater/air-conditioning unit must not be damaged.
Checking the mounts for the stars on the heater/air-conditioning unit
Installing heater/air-conditioning unit
1. Position the heater/air-conditioning unit in the vehicle with the help of a second person -arrow A-. Get this person to check that the stars are positioned correctly and turn them if necessary.
2. Slide the heater/air-conditioning unit onto the two mounts (stars) and clip it in at two retaining points on the left and right. Get a second person to check that the mounts (stars) are positioned correctly and turn them if necessary.
3. Clip in the main wire harness and cable duct at the heater/air-conditioning unit at the left and right -arrow B-.
4. Push the water drain hose onto the air-conditioning unit and make sure it is seated correctly. Slide on the clamp -3-.
Pushing on water drain hose
5. Clip in the main wire harness and cable duct at the heater/air-conditioning unit at the left and right.
6. Plug in electric plug connection for the servo motors until it engages securely.
Plugging in connector for servo motors
7. Insert the centre air vents for the footwell and slide them onto the heater/air-conditioning unit. -> 805519 Removing and installing front footwell outlet vent - section on "Installing" 805519 Removing and installing front footwell outlet vents
Information
- Always replace O-rings.
8. Insert the coolant supply line and return line into the heat exchanger -arrow B-.
9. Slide on the retaining clips -2- until they engage securely.
Sliding on retaining clips for coolant line
10. Fit cover for coolant lines.
Fitting cover for coolant lines
11. Screw in two fastening screws -1- on the cover.
Subsequent work
1. Install dashboard bracket. -> 701219 Removing and installing dashboard bracket - section on "Subsequent work"
2. Fill in coolant. -> 193817 Draining and filling coolant - section on "Filling" Service and Repair
3. Bleed the cooling system. -> 190101 Checking the cooling system - section on "Bleeding" Testing and Inspection
4. Fill in refrigerant. -> 870317 Draining and filling refrigerant - section on "Filling" Service and Repair
5. Check the heating system for leaks.