Climate Control Systems
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14.1 SYSTEM DESCRIPTION
The Air Conditioning electronic Control Module (A/ CCM) located on the right-hand side of the A / C unit, controls the 0 functions of the system.
These functions include:
0 In-car temperature control
0 In-car humidity control (Air conditioning vehicles only)
0 Air flow / volume and distribution
The temperature of the passenger compartment is continuously compared with the temperature selected on the con
- trol panel LCD. A digital microprocessor within the A/ CCM receives the data signals. Comparison of these signals
and those from system temperature sensors and feedback devices results in the appropriate output voltage changes
needed to vary the blend of air flow into the passenger compartment.
The climate control system peripherals communicate with the A/ CCM via three main device categories comprising
of manual inputs, automatic outputs and inputs, as shown
in Fig. 1.
Air Temperature Control I
9 Recirculation switch
. Air con on/off switch
System on/off switch
. Auto. / Man. select
Set temperature
. Air flow outlet mode set
Heated front screen switch
. Heated rear screen &
heated mirror switch
. External temp. display
switch
. FahrenheiVCentigrade switches
4
. Solar sensor
. Motorized in-car aspirator
. Ambient temp. sensor
. Evaporator temp. sensor
Heater matrix temp. sensor
. Compressor lock sensor
. Face differential temp. control
. Refrigerant pressure switch
. Engine speed signal
Engine coolant temperature
Vehicle speed signal
. Circulation pump
. Water valve
. Power transistor (fan speed
Servo motor potentiometers:
signal
control)
LH air inlet flap
RH air inlet flap
Centre vent flap
Foot flap
Defrost flap
Air by
-pass flap
Air Inlet Control
9 LH air inlet
. RH air inlet
CONTROL PANEL
1
A / CCM
I I
I . External temp. display I
. Coolant recirculation valve
. Coolant recirculation pump
LH blower motor & power transistor
. RH blower motor & power transistor
. LH high speed relay
Air Distribution Control
Servo motor for:
9 Centre vent flap
Foot flap
Defrost flap
Fig. 1 Schematic view A / CCM Inputs & Outputs
X300 EDM 1 Issue 1 August 1994
Climate Control Systems
14.2.16 Servo Motor Control
The system incorporates several servo motors which direct the flow of air through the air conditioning system. The
motors are driven by A / CCM signals in either a clockwise or anti-clockwise direction.
Servo motor position is monitored via
a feedback potentiometer situated within the motor housing.
The system servos comprise:
o RH and LH Air intake servos (Fresh / Recirc.).
0 Centre vent servo.
o Defrost (screen vent) servo.
0 Footservo.
0 Cool air by-pass servo.
14.2.17 Blower Motor Control
The A/ CCM controls two blower motors, delivering airflow
to the evaporator / heater unit, at variable fan speeds. The
blower motors are regulated by power transistor modules
which provide linear variation of blower speed; the blower
speed
is increased or reduced progressively in response to
vehicle speed, minimising the ram effect of forward motion.
The blower motors are inhibited when engine coolant tem
- perature is below 30°C and heating is requested.
14.2.18 Differential Control
The differential control is mounted on the facia centre vent. It is used to control the temperature difference between the
upper and lower outlets. Fig.
1 Servo
Motor
14.2.19 Heated Rear Window, Door Mirrors and Front Screen
The Heated Rear Window (HRW) function can only be activated with the ignition on and the engine running. Operation of the HRW switch operates the status condition LED on the control panel and switches on the HRWfor approximately 21 minutes. Selection of the HRW also operates the door mirror heaters for approximately 11 minutes. The operation
can be cancelled by switch re-selection or ignition off. System off does not cancel the HRW operation.
The Heated Front Screen
(HFS) function can only be activated with the ignition on and the engine running, and either
‘defrost’ mode selected or HFS selected. Each half, left and right hand split, switches on for approx. 6.5 minutes. The
operation can be cancelled by switch re-selection or ignition off. System off does not cancel the HFS operation.
0
0
Issue 1 August 1994 6 X300 EDM
15.4 DRIVER ERGONOMICS
15.4.1 System Description
Adjustment of the seats, steering column and exterior rear view mirrors position is effected by means of control
switches. The switches maintain the adjustment facility while depressed, movement ceasing when the switch is re- leased.
Manual adjustment can be achieved either with the ignition key in place or with the driver‘s door open, or having been
closed within the last
30 seconds.
The system offers the following facilities:
Entry
/ Exit mode; an automatic seat /column position setting for ease of driver entry into / exit from the vehicle.
Driving position set; automatic recall of up to three preferred settings.
Passenger seat set; automatic recall of up to three preferred settings.
Remote recall; automatic recall of up to two memory positions from
a remote transmitter (in key fob).
Reverse mirror dip; automatic adjustment of passenger rear view mirror when reversing.
U: Vehicles intended for the Japanese market are fitted with an additional ‘fold away’ mirror function. This func- tion allows mirrors to fold flat against the car when parking in enclosed areas.
15.4.1.1 Entry/ Exit Mode
Entry / Exit mode is designed to give easier vehicle entry and exit for the driver. The facility is selected by positioning
the mode switch, located on the LH side of the column cowl, to ‘auto’ which designates the current seat / column posi- tion, ie driving positions, as the memorized position. On removal of ignition key or opening of driver‘s door, with igni- tion key still in place, the driver’s seat will move to the rear (current position allowing) and the column will adopt ‘tilt
away’ mode automatically creating additional space for driver exit
/ entry. Insertion of key in ignition or closure of
driver‘s door (with ignition key in place) returns seat / column positions to the memorized (previous) position.
Operation of eitherthe brake pedal or
seat/column manual controls during entry/exit mode execution will abort posi- tional adjustments. Setting the mode switch to OFF disables operation of entry / exit mode.
15.4.1.2 Driving Position Set
Setting of seat, column and external rear view mirrors to preferred driving position is available using the memory but- tons located on the drivers door switch pack. With the ignition key in place enter settings to be memorized as follows:
Adjust seat, column and mirrors to desired positions.
Press the ’memory’ button
so that it becomes illuminated.
Press button
1,2 or 3 to store configuration within four seconds of memory button operation. Memory light will extin- guish and a chime will sound, indicating procedure complete.
The above procedure may be repeated two more times until each button
(1,2 & 3) has a preferred position stored in
memory, accommodating different driver settings. Operation of any push-button (1,2 or 3) will re-position seat col-
umn and mirrors to the stored settings.
Memory recall will operate under the following conditions:
. Ignition key in and gear selector in park.
8 Ignition key in and handbrake on.
8 Ignition key out and driver’s door open (or having been closed within the last 30 seconds).
Re
-setting the preferred position on any setting button automatically erases previously stored information. Memory
information is not erased if power supply to the seat and column / mirror control modules is lost (e.g. battery discon- nected).
15.4.1.3 Passenger Seat Set
The procedure for setting and recalling a preferred passenger seat position is identical to that for a driving position.
Memory recall will only operate with ignition key in auxiliary position or passenger door open, or having been closed
within the last
30 seconds.
X300 EDM 15.4 - 1 Issue 1 August 1994
E I ect r ical
15.4.2.5 Switch pack
The seat switch pack located on the side of the seat cushion houses the following switches:
Headrest; raise
/ lower
Seat cushion
-front; raise 1 lower
Seat cushion
- rear; raise 1 lower
Squab recline
/ incline
Seat assembly forward
/ backward
Lumbar pad firm
1 relax
Each switch has
a dual function and is capable of bi-directional action, so that any setting made can be reversed using
the same switch.
15.4.3 SEAT CONTROL MODULE
The Seat Control Module (SCM) is located inside the seat frame, below the cushions. The SCM controls the actions
of all position adjustment devices by monitoring switch and feedback potentiometer inputs. The SCM also provides
an interface to and from external devices with a bearing on seat operation. The module works in conjunction with the
ColumnIMirror Control Module (C/M CM) and the Securityand Locking Control Module (S/LCM) to provide positional adjustment memory functions as described previously.
There are four connectors to the SCM, designated
AI, A2, B1 and B2, which connect the various inputs 1 outputs and
peripheral devices to the module. Connections are as listed in subsection 15.4.3.1.
A1A2 B1B2
1 1 1
i 11
1 I
6
I
1' ~
1 7i 1 I 1 122
J86 1903 12 22 12 12 7 12
Fig. 1 SCM
Pin Location Diagram
X300 EDM 15.4 - 5 Issue 1 August 1994
IT Electrical
15.4.5 COLUMN / MIRROR CONTROL MODULE
The Column / Mirror Control Module C/ M CM controls the operation of position adjustment motors by acting upon
inputs from the relevant switches. The module also forms an interface with signals from associated systems which
affect column /mirror movement. The
C/ M CM works in conjunction with SCM and SL CM to provide positional adjust- ment memory functions as previously described.
There are three connectors to the
C I M CM single multi-pin socket, designated block A, B and C, which connect the
various inputs / outputs and peripheral devices to the module. Connections are as listed below.
I BLOCK A [26-WAY GREY) 1
I .. I I 41 Input Switched to 12V ..
20 Memory set selected
Input Switched to 12V
21
Tilt restrict ident Input Switched to ground 1 open
22 Key in ignition barrel active
Input Switched to ground
circuit
23
1 Auxiliary ground on Input 1 Switched to ground
24 1 Reference voltage +ve feedback output I4.5v
25 1 Passenger mirror R/L Output 1 +ve 1 -ve
26
1 Mirror motor common Output I +ve / -ve
BLOCK B (lgWAY, GREY)
Pin No. I Description I In / out lsignal
1 Driver mirror L/R feedback Input 140mV - 4.36V
2 Passenger U/D feedback
Input 140mV - 4.36V
3 Driver mirror U/D feedback Input 140mV - 4.36V
4 Column tilt feedback Input 140mV - 4.36V
5 Column reach feedback
input 140mV - 4.36V
6 Reverse gear selected
Input Switched to ground
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