Auxiliary HVAC Control System: Other Mercury Montego III

Auxiliary Climate Control System

The auxiliary climate control housing is located on the LH side of the vehicle between the side windows and the floorpan, behind the rear wheel well. The driver has primary control of the auxiliary climate control system or can transfer control to a rear passenger control panel.

All of the auxiliary climate control system components are serviceable from the inside of the vehicle except the lines.

Auxiliary System Air Distribution

A vertical air distribution duct supplies air to the integral headliner air distribution duct. Airflow is then directed to the passengers through adjustable registers. The heater floor duct supplies air to a fixed register, which is integral to the side trim panel.

Scheme 31

The auxiliary climate control system has the following features

1. The auxiliary blower motor recirculates the air inside the vehicle. Outside air is not available to the auxiliary climate control system.
2. Air is cooled and dehumidified by the auxiliary evaporator core only if the main (front) climate control assembly is adjusted to a position that requires A/C compressor operation.
3. The temperature blend door and the airflow mode door are controlled by electric actuator motors.
4. Movement of the auxiliary temperature/mode control between COOL/ROOF and WARM/FLOOR causes a corresponding movement of the temperature blend door to mix air flowing through and around the auxiliary heater core and also causes a corresponding movement of the mode door to the ROOF and FLOOR positions.

Blower Motor

The auxiliary climate control system contains a blower motor, which is controlled by the blower motor switch on the front or rear auxiliary climate control assembly.

Evaporator Core

The auxiliary climate control system uses an evaporator core, which cools and dehumidifies the airflow from the auxiliary blower motor when the A/C compressor is operating. All airflow from the blower motor passes through the evaporator core.

Heater Core

The heater core consists of fins and tubes arranged to extract heat from the engine coolant and transfer it to air passing through the heater core.

Thermostatic Expansion Valve

The thermostatic expansion valve (TXV) is located behind the LH rear quarter trim panel at the auxiliary evaporator inlet and outlet. The TXV provides a restriction to the flow of refrigerant from the high-pressure side of the refrigerant system and separates the low-pressure and high-pressure sides of the refrigerant system. Refrigerant entering and exiting the evaporator core passes through the TXV through 2 separate flow paths. An internal temperature sensing bulb senses the temperature of the refrigerant flowing out of the evaporator core and adjusts an internal pin-type valve to meter the refrigerant flow into the evaporator core. The internal pin-type valve decreases the amount of refrigerant entering the evaporator core at lower temperatures and increases the amount of refrigerant entering the evaporator core at higher temperatures.

Underbody Auxiliary A/C Lines

The underbody auxiliary A/C lines carry refrigerant to the auxiliary A/C evaporator inlet, and away from the auxiliary A/C evaporator outlet. The auxiliary underbody lines have the following characteristics

1. The auxiliary evaporator inlet line carries high-pressure refrigerant liquid from the TXV manifold and tube assembly to the auxiliary evaporator.
2. The auxiliary evaporator outlet line carries refrigerant vapor from the auxiliary evaporator to the TXV manifold and tube assembly.

Underbody Heater Lines

The underbody auxiliary heater lines have the following features

1. The underbody auxiliary heater inlet line is a aluminum tube assembly that carries coolant from the engine coolant supply line to the auxiliary heater core inlet.
2. The underbody auxiliary heater outlet line carries coolant from the auxiliary heater core to the front heater core outlet line.

Auxiliary Climate Control

Refer to CLIMATE CONTROL SYSTEM-GENERAL INFORMATION .

Material

MATERIAL CHART

Scheme 32

Scheme 33

MATERIAL CHART

Scheme 34

Note. The auxiliary evaporator inlet and outlet lines are not supplied together as an assembly. The auxiliary evaporator inlet line and outlet line are each installed from the factory as one-piece assemblies. The replacement parts are supplied as separate kits containing 2-piece lines for ease of installation.

Note. The following procedure can be used to remove and install one or both of the auxiliary evaporator inlet line and auxiliary evaporator outlet lines. If only one auxiliary evaporator line is to be removed and installed, cut or disconnect only the desired line at the specified points within the procedure.

1. Recover the refrigerant. For additional information, refer to «CLIMATE CONTROL SYSTEM-GENERAL INFORMATION»(ref-233047) .
2. Position a jack stand to support the muffler and tailpipe assembly.
3. Disconnect the resonator isolator.
4. Disconnect the underbody catalytic convertor and discard the gasket.
5. Disconnect the muffler front isolator.
6. Disconnect the muffler rear isolator.
7. Remove the muffler, resonator and underbody catalytic convertor assembly.
8. Remove the rear driveshaft. For additional information, refer to «DRIVESHAFT»(ref-233022) .
9. Remove the exhaust heat shield.
10. Remove the auxiliary evaporator inlet line fitting nut and disconnect the fitting. Discard the O-ring seal. To install, tighten to 8 Nm (71 lb-in).
11. Remove the auxiliary evaporator outlet line fitting nut and disconnect the fitting. Discard the O-ring seal. To install, tighten to 8 Nm (71 lb-in).
12. Remove the LH rear wheel.
13. Remove the LH rear quarter panel moulding. For additional information, refer to «EXTERIOR TRIM AND ORNAMENTATION»(ref-233040) .
14. Remove the 3 outer LH rear quarter panel moulding bracket bolts.
15. Remove the 2 inner LH rear quarter panel moulding bracket bolts.
16. Remove the LH rear quarter panel moulding bracket. Detach the splash shield pin-type retainer.
17. Remove the 2 LH rear brake caliper bolts and position the caliper aside. To install, tighten to 35 Nm (26 lb-ft).
18. Remove the 2 parking brake cable bolts. To install, tighten to 12 Nm (9 lb-ft).
19. Remove the 4 rear subframe bracket bolts. To install, tighten to 63 Nm (46 lb-ft).
20. Remove and discard the trailing arm-to-knuckle bolt. To install, tighten to 110 Nm (81 lb-ft).
21. Loosen the trailing arm-to-subframe bolt and position the trailing arm aside. To install, tighten to 110 Nm (81 lb-ft).
22. Remove the LH lower shock bolt. To install, tighten to 142 Nm (105 lb-ft) for AWD. To install, tighten to 110 Nm (81 lb-ft) for FWD.
23. Position a lifting table to support the rear subframe.
24. With a wax pencil, mark the relational alignment of the rear subframe to the underbody at the mounting locations.
25. Disconnect the 2 rear wheel speed sensor electrical connectors.
26. Loosen, but do not completely remove the 2 RH rear subframe bolts. To install, tighten to 115 Nm (85 lb-ft).
27. Remove the 2 LH rear subframe bolts. To install, tighten to 115 Nm (85 lb-ft).
28. Correctly support the fuel tank and remove the LH rear fuel tank strap bolt. To install, tighten to 35 Nm (26 lb-ft).
29. Remove the rear auxiliary inlet line fitting nut and disconnect the fitting. Discard the O-ring seal. To install, tighten to 8 Nm (71 lb-in).
30. Remove the rear auxiliary outlet line fitting nut and disconnect the fitting. Discard the O-ring seal. To install, tighten to 8 Nm (71 lb-in).
31. Remove the 2 middle rear auxiliary line bracket bolts. To install, tighten to 5 Nm (44 lb-in).
32. Remove the 2 middle rear auxiliary line brackets.
33. Remove the 2 middle front auxiliary line bracket nuts. To install, tighten to 5 Nm (44 lb-in).
34. Remove the 2 middle front auxiliary line brackets.
35. Assemble and lay out the replacement line(s) in the same position as the existing line(s) and, using a suitable tool, cut the auxiliary evaporator line(s) in the same position as the middle fitting on the replacement line(s). To install, connect the middle auxiliary evaporator line fitting(s).
36. Remove the front auxiliary line bracket nut. To install, tighten to 5 Nm (44 lb-in).
37. Remove the front auxiliary line bracket.
38. Remove the front portion of the auxiliary evaporator outlet line and/or auxiliary evaporator inlet line.
39. Remove the rear auxiliary line bracket nut. To install, tighten to 5 Nm (44 lb-in).
40. Remove the rear auxiliary line bracket.
41. Remove the rear portion of the auxiliary evaporator outlet line and/or the auxiliary evaporator inlet line.
42. To install, reverse the removal procedure. Install new O-ring seals. Lubricate the refrigerant system with the correct amount of clean PAG oil. For additional information, refer to «CLIMATE CONTROL SYSTEM-GENERAL INFORMATION»(ref-233047) .
43. Evacuate, leak test and charge the refrigerant system. For additional information, refer to «CLIMATE CONTROL SYSTEM-GENERAL INFORMATION»(ref-233047) .

Scheme 35

1. Remove the LH quarter trim panel. For additional information, refer to «INTERIOR TRIM AND ORNAMENTATION»(ref-233049) .
2. Disconnect the auxiliary temperature blend door actuator electrical connector.
3. Remove the 3 auxiliary temperature blend door actuator screws.
4. Remove the auxiliary temperature blend door actuator.
5. To install, reverse the removal procedure.

Scheme 36

1. Remove the LH quarter trim panel. For additional information, refer to «INTERIOR TRIM AND ORNAMENTATION»(ref-233049) .
2. Disconnect the auxiliary blower motor resistor electrical connector.
3. Remove the 2 auxiliary blower motor resistor screws.
4. Remove the auxiliary blower motor resistor.
5. To install, reverse the removal procedure.

Scheme 37

1. Remove the LH quarter trim panel. For additional information, refer to «INTERIOR TRIM AND ORNAMENTATION»(ref-233049) .
2. Disconnect the auxiliary mode door actuator electrical connector.
3. Remove the 2 auxiliary mode door actuator screws.
4. Remove the auxiliary mode door actuator.
5. To install, reverse the removal procedure.