JAGUAR XFR 2010 1.G Workshop Manual

Climate Control - Heating and Ventilation - Overview
Description and Operation

Overview Published: 11-May-2011

The heating and ventilation system controls the temperature and flow of air supplied to the passenger compartment. The
system is a dual zone automatic system, which can provide different temperature settings for the LH (left-hand) and RH
(right-hand) sides of the passenger compartment.

Published: 11-May-2011
Climate Control - Heating and Ventilation - System Operation and Component Description
Description and Operation

Control Diagram

NOTE: A = Hardwired; N = Medium speed CAN (controller area network) bus; O = LIN (local interconnect network) bus; P
= Media orientated system transport (MOST) ring.



Item Description 1 Battery 2 BJB (battery junction box) 3 CJB (central junction box) 4 Auxiliary coolant pump Comments:
all except 3.0L vehicles; 5.0L version shown, 3.0L diesel version similar www.JagDocs.com

Touch screen display (TSD) 6 Integrated control panel 7 Information control module 8 ATC (automatic temperature control) module 9 Face/Feet distribution stepper motor 10 RH (right-hand) temperature blend stepper motor 11 LH (left-hand) temperature blend stepper motor 12 Windshield (defrost) distribution stepper motor 13 Blower control module 14 RJB (rear junction box) 15 Blower
System Operation
Operation of the heating and ventilation system is controlled by the ATC module. Refer to: Control Components (412-01 Climate Control, Description and Operation).
The system can be operated in automatic or manual mode, with temperature settings selected using the switches on the
integrated control panel.

When the engine is running, coolant is constantly circulated through the heater core by the engine coolant pump and the
auxiliary coolant pump. Where fitted, the auxiliary coolant pump is energized by the CJB on receipt of medium speed CAN bus signals from the ATC module. The CJB broadcasts auxiliary coolant pump status over the medium speed CAN bus for use by other vehicle systems.

The blower is supplied with power by the blower relay on the RJB and connected to ground via the blower control module. The blower control module regulates the voltage across the blower motor to control blower speed. The voltage set by the blower
control module is controlled by a PWM (pulse width modulation) signal from the ATC module. The ATC module uses a feedback signal from the blower control module to monitor blower speed.
Refer to: Control Components (412-01 Climate Control, Description and Operation).


Heater Assembly Component Description

The heater assembly controls the temperature and flow of air supplied to the air distribution ducts. The heater assembly is
mounted on the vehicle centerline, between the instrument panel and the engine bulkhead.

The heater assembly consists of a casing that contains an A/C (air conditioning) evaporator, a heater core, two air distribution
control doors and two temperature blend control doors. On 2.7L diesel vehicles, the heater assembly also contains an electric
booster heater.
Refer to: Electric Booster Heater (412-02 Auxiliary Climate Control, Description and Operation).
Mounted on the heater casing are four stepper motors. Each of the stepper motors is connected to either an air distribution
control door or a temperature blend control door.
The A/C evaporator is part of the A/C system. Refer to: Air Conditioning (412-01 Climate Control, Description and Operation).
The heater core provides the heat source to warm the air supplied to the passenger compartment. The heater core is an
aluminum two pass, fin and tube heat exchanger, and is installed across the width of the heater housing. Two aluminum tubes
attached to the heater core extend through the engine bulkhead and connect to the engine cooling system. For additional
information, refer to:
Engine Cooling (303-03A, Description and Operation),
Engine Cooling (303-03B Engine Cooling - V6 3.0L Petrol, Description and Operation), Engine Cooling (303-03C, Description and Operation).

Air Inlet Duct

The air inlet duct connects the fresh air inlet in the engine bulkhead to the heater assembly. The air inlet duct is installed
behind the instrument panel on the passenger side.

The air inlet duct consists of a casing that contains a pollen filter, an air inlet door, a blower and a blower control module. A
recirculation air inlet is incorporated into the casing. A servo motor is mounted on the casing and connected to the air inlet
door, to allow selection between fresh and recirculated air.
Refer to: Control Components (412-01 Climate Control, Description and Operation). The pollen filter is part of the air distribution and filtering system.
Refer to: Air Distribution and Filtering (412-01 Climate Control, Description and Operation).
The blower regulates the volume of air flowing through the air inlet duct to the heater assembly. The blower consists of an
open hub, centrifugal fan and an electric motor.
The blower control module regulates the power supply to the blower motor. The blower control module is installed in the air

inlet duct downstream of the blower, where any heat generated during operation is dissipated by the air flow.

Auxiliary Coolant Pump

On all vehicles except 3.0L, an auxiliary coolant pump is installed on the rear right side of the radiator housing, in the return
line from the heater core. The auxiliary coolant pump is an electric pump that boosts the flow of coolant through the heater
core.

Ventilation Outlets

The ventilation outlets allow the free flow of air through the passenger compartment. The outlets are installed in the LH and
RH rear quarter panels, below the rear lamps. Each ventilation outlet consists of a grille covered by a soft rubber flap, and is
effectively a non-return valve. The flaps open and close automatically depending on the pressure differential between the air
inside and outside the vehicle.

Climate Control - Air Conditioning - Component Location
Description and Operation


NOTE: LHD (left-hand drive)  .L vehicle shown, other vehicles sim ilar.

Component Location Published:
11-May-2011



Item Description 1 Evaporator
2 Thermostatic expansion valve
3 Low pressure line
4 Low pressure servicing connection
5
A/C (air conditioning) compressor 6 Receiver/Drier
7 Condenser

9 High pressure line 10 High pressure servicing connection

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Published: 11-May-2011
Climate Control - Air Conditioning - System Operation and Component Description
Description and Operation


General System Operation

To accomplish the transfer of heat, refrigerant is circulated around a sealed system, where it passes through two
pressure/temperature regimes. In each of the regimes the refrigerant changes state, during which process maximum heat
absorption or dissipation occurs.

The low pressure/temperature regime is from the thermostatic expansion valve, through the evaporator to the compressor. The
refrigerant decreases in pressure and temperature at the thermostatic expansion valve, then changes state from a liquid to a
vapor in the evaporator to absorb heat.

The high pressure/temperature regime is from the compressor, through the condenser and receiver drier assembly to the
thermostatic expansion valve. The refrigerant increases in pressure and temperature as it passes through the compressor, then
releases heat and changes state from a vapor to a liquid in the condenser.

Operation of the A/C (air conditioning) system is controlled by the ATC (automatic temperature control) module.
Refer to: Control Components (412-01 Climate Control, Description and Operation). The A/C system works in conjunction with: The air distribution and filtering system.
Refer to: Air Distribution and Filtering (412-01 Climate Control, Description and Operation). The heating and ventilation system.
Refer to: Heating and Ventilation (412-01 Climate Control, Description and Operation).

1 Evaporator 2 Thermostatic expansion valve 3 High pressure servicing connection 4 Refrigerant pressure sensor 5 Engine cooling fan 6 Condenser 7 Receiver/Drier 8 A/C compressor 9 Low pressure servicing connection 10 Blower NOTE: A = Refrigerant liquid; B = Refrigerant vapor; C = Air flow.

1 Pressure relief valve 2 Outlet port 3 Inlet port 4 Solenoid valve 5 Electrical connector 6 Pulley The A/C compressor circulates refrigerant around the system by compressing low pressure, low temperature vapor from the evaporator and discharging the resultant high pressure, high temperature vapor to the condenser.

The A/C compressor is a permanently engaged variable displacement unit which is driven by the engine accessory drive belt. To protect the system from excessive pressure, a pressure relief valve is installed in the outlet side of the A/C compressor. The pressure relief valve vents excess pressure into the engine compartment.