Housing Assembly HVAC: Service and Repair
WM 851519 Removing and installing heating/fresh air unit
Technical values
Preliminary work
Preliminary work for heating/fresh air unit
1. Drain refrigerant. -> 870317 Draining and filling in refrigerant - section on "draining"
2. Drain engine coolant. -> 193817 Draining and refilling coolant
3. Remove dashboard. -> 701819 Removing and installing dashboard - section on "Removing" 701819 Removing and installing instrument panel
4. Remove tunnel support. -> 684419 Tunnel support - section on "Removing" 684419 Removing and installing tunnel support
5. Remove passenger's airbag unit. -> 695919 Removing and installing passenger's airbag unit - section on "Removing" 69591900 Removing and installing passenger's airbag unit
6. Remove battery. -> 270619 Removing and installing battery - section on "Removing" 27061900 Removing and installing battery
7. Remove right plenum panel cover. -> 852219 Removing and installing cover - section on "Removing" 85221900 Removing and installing cover
8. Remove heat exchanger. -> 802319 Removing and installing heat exchanger - section on "Removing"
Removing heating/fresh air unit
Information
- Make sure not to damage the insulation of the main wiring harness.
Installation position shown on the 911
1. Immediately seal the openings of air-conditioning lines with suitable plugs.
2. Unscrew fastening screw -1- for refrigerant line -C- and open the pressure line.
Opening pressure line
3. Unscrew fastening screws -2- and remove expansion valve. -> 877019 Removing and installing expansion valve - section on "Removing"
Removing expansion valve
4. Unscrew the fastening nuts -6- for the heater/air-conditioning unit in the area of the plenum panel/firewall.
Fastening nuts for heater/air-conditioning unit
5. Unscrew fastening screw -3- for securing holder of the heater/air-conditioning unit to right side of dashboard bracket (next to A-pillar).
Fastening screw to dashboard bracket
6. Unscrew fastening screw -4- for securing heater/air-conditioning unit to right side of dashboard bracket (passenger's side).
Fastening screw to dashboard bracket
7. Unscrew the two fastening screws -5- for dashboard bracket to right side of body.
Fastening screws on dashboard bracket
8. Unclip holder for electric harness with a screwdriver from right side of dashboard bracket.
Unclipping wire harness at dashboard bracket.
9. Now pull dashboard bracket a few centimeters forward on the right side.
Pulling dashboard bracket forward
10. Pull out cotter pin -A- for holder of the heater/air-conditioning unit.
Removing cotter pin
11. Turn holder -B- for heater/air-conditioning unit by 90° and pull up and out.
Pull out holder
12. Lay down the air conditioner, release clamp for water drain hose -C- and pull off the water drain hose from the heater/air-conditioning unit.
Pulling off water drain hose
13. Carefully lift heater/air-conditioning unit forward with a screwdriver under the right side of the dashboard bracket.
Lifting heater/air-conditioning unit forward under the dashboard bracket
14. Release lower plug connection on heater/air-conditioning unit -a- and unplug.
Releasing electric plug connection
15. Release upper plug connection on heater/air-conditioning unit -a- and unplug.
Releasing electric plug connection
16. Cut tie-wraps of electric line (vehicle wire harness to heater/air-conditioning unit wire harness) with side cutters. Remove vehicle wire harness.
Cutting tie-wraps
17. Pull air conditioner forward on the right side, unscrew fastening screw -7- for B+ line holder and remove holder for heater/air-conditioning unit.
Unscrewing holder for B+ line
18. Pull/push heater/air-conditioning unit as far as possible in direction of passenger's seat.
Pulling out heater/air-conditioning unit
19. Remove heater/air-conditioning unit from passenger compartment via passenger's door.
Heating/air-conditioning unit
Installing heating/fresh air unit
Information
Do not remove the stoppers for the air-conditioning lines until just before installing the expansion valve.
Check foam parts for signs of damage. If in doubt, replace them.
1. Insert heater/air-conditioning unit in the vehicle over the passenger's side.
Placing heater/air-conditioning unit in the vehicle
2. Lift heater/air-conditioning unit over the centre console and position under dashboard bracket.
Positioning heater/air-conditioning unit
3. Position holder for the B+ line on the heater/air-conditioning unit and tighten with the fastening screw -7-. => Tightening torque: 1.7 Nm (1.5 ftlb.)
Tightening holder for B + lead
4. Lay electric line from vehicle wire harness to heater/air-conditioning unit wire harness and fix with a tie-wrap.
Fastening electric line
5. Connect upper electric plug connection at heater/air-conditioning unit until it is felt to engage.
Connecting upper electrical plug connection
6. Connect upper electric plug connection at heater/air-conditioning unit until it is felt to engage.
Connecting lower electrical plug connection
7. Check water drain hose for damage; if drain hose shows no sign of damage, connect hose to the drain on heater/air-conditioning unit and fix with the clamp -C-.
Fixing water drain hose
8. Push heater/air-conditioning unit into position under right side of dashboard bracket in the direction of firewall.
Positioning heater/air-conditioning unit
9. Guide holder -B- for the heater/air-conditioning unit over the dashboard bracket, push through the mounting of the heater/air-conditioning unit and turn through 90°.
Positioning holder for heater/air-conditioning unit
10. Fix holder for heater/air-conditioning unit with cotter pin -A-.
Holder for heater/air-conditioning unit
11. Push dashboard bracket forwards while lifting the heater/air-conditioning unit and taking care that no electric lines get trapped.
Pushing dashboard bracket forwards
12. Screw down dashboard bracket with the two fastening screws -5-. => Tightening torque: 23 Nm (17 ftlb.)
Securing dashboard bracket
13. Clip in the plastic holders for the electric main wire harness to the dashboard bracket.
Clipping in plastic holders
14. Secure dashboard bracket with the fastening screw -4-. => Tightening torque: 9.7 Nm (7.0 ftlb.)
Securing dashboard bracket
15. Screw down holder of heater/air-conditioning unit with the fastening screw -3-. => Tightening torque: 3.5 Nm (2.5 ftlb.)
Securing holder for heater/air-conditioning unit
16. Slide the fastening bolts of the heater/air-conditioning unit through the firewall lid and tighten with the three fastening nuts -6-. => Tightening torque: 9.7 Nm (7.0 ftlb.)
Securing heater/air-conditioning unit to firewall
Information
Do not remove the stoppers for the air-conditioning lines until just before installing the expansion valve.
Check foam parts for signs of damage. If in doubt, replace them.
17. Install expansion valve and tighten with the two fastening screws -2- , replace sealing rings for refrigerant lines and wet them with refrigerant. -> 877019 Removing and installing expansion valve - section on "Installing"=> Tightening torque: 9 Nm (6.5 ftlb.)
Installing expansion valve
18. Replace sealing rings for refrigerant lines and wet with refrigerant. Position refrigerant line and tighten with fastening screw -1-. => M8: 14 Nm (10.5 ftlb.)
Positioning and securing refrigerant lines
Subsequent work
Subsequent work for heater/air-conditioning unit
1. Install heat exchanger -> 802319 Removing and installing heat exchanger - section on "Installing"
2. Install passenger's airbag unit. -> 695919 Removing and installing passenger's airbag unit - section on "Installing" 69591900 Removing and installing passenger's airbag unit
3. Install tunnel support. -> 684419 Tunnel support - section on "Installing" 684419 Removing and installing tunnel support
4. Install dashboard. -> 701819 Removing and installing dashboard - section on "Installing" 701819 Removing and installing instrument panel
5. Install and connect the battery. -> 270619 Removing and reinstalling battery - section on "Installing" 27061900 Removing and installing battery
-> 271000 Work instruction after disconnecting battery 2706IN00 Work instructions after disconnecting the battery
6. Fill in refrigerant. -> 870317 Draining and filling in refrigerant
7. Top up engine coolant. -> 193817 Draining and refilling coolant
8. Install right cover for plenum panel. -> 852219 Removing and installing cover - section on "Installing" 85221900 Removing and installing cover