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on the engine accessory drive. As such the power train ECM/PCM owns the hardware and
software for compressor engagement. The HVAC function can issue a request for
compressor but this request is always arbitrated by power train logic. The logic implemented
for the Air conditioning function for both the HVAC control head as well as the PCM depend
on the style of hardware implementation for the compressor. The PPEI interface
specification is the basic document for this operation.
Air distribution mode
The HVAC system controls the direction of airflow into the vehicle based on user input using
the buttons on the front of the HVAC controller. It can also be controlled due to Remote
Start, Park Heater, Afterblow and Auto Climate control. The modes available for air
direction are
panel
floor
Bi-level
Defog
Windshield
Tri-Level
Hi-Level (panel + windshield)
Air recirculation
Air Recirculation is turned on via user input or due to remote start, comfort algorithm
operation, Park heater operation or Auxiliary heater operation.
Auxiliary Heater
The electrical auxiliary heater (AHS) is utilized to provide enough heat quantity in the
vehicle compartment at low outside temperatures. It provides support to the heat
exchanger at low coolant temperatures. The system consists of Positive Temperature
Coefficient semiconductors (PTC) that are controlled by an electrical control module and
electrical power distributor.
Blower setting control
The HVAC system controls fan Blower Setting based on user input on the faceplate. Blower
may also be activated for afterblow, park heater, rest heat, comfort algorithm, load shed or
Remote Start. Blower setting is adjusted for OnStar hands free calling and air bag
deployment.
Comfort control
The HVAC comfort control system collects user HVAC control settings information along
with sensor information and other control function status information. With that information
the comfort control determines the required state of the HVAC actuators, blowers, pumps
etc. It also defines what information will be displayed or indicated back to the customer.
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Comfort control handles these determinations for both front and auxiliary HVAC modules
and associated control elements.
Data manager / Fail soft
The HVAC Data Manager / Fail Soft (FS) function provides basic input and strategic input
fail soft values for the HVAC. CCA (Climate Comfort Application) should input signals that
are missing or invalid. Data signals into the CCA which require filtering or failsofting will be
passed from this routine. The routine shall also provide a validity flag for each signal passed
into subsequent CCA routines to be used to trigger additional Fail Soft logic where the
validity of a certain signal is critical to the function.
Driver personalization
Driver personalization includes the following two items:
1. Controller stores individual settings for multiple drivers
2. Controller allows settings to be customized by the driver either through a vehicle user
interface or via a test tool at the dealership.
Driver temperature control
The HVAC system controls the driver temperature based on input from the user or comfort
algorithm. It is also adjusted due to remote start, Park Heater, REST and afterblow.
Heater pump control
The mechanization defined in this section is applicable to all vehicle applications using a
electrically driven coolant pump with Global A electrical architecture.
The Heater Core Coolant Pump Control is used to assist coolant flow for three major
functions:
1. In Hybrid Vehicles this control will command the coolant pump to circulate engine
coolant when the engine is off (Auto-stopped) and heat is required in the cabin for
comfort.
2. In vehicles with REST functionality and coolant pump hardware, this control will
command the coolant pump to circulate engine coolant when the engine is off and
the REST function is active.
3. In conventional vehicles requiring heater core flow assist at idle, this control will
command the coolant pump to circulate engine coolant in extremely cold conditions
to supplement the mechanical engine coolant pump.
Idle boost
Upon entering the run power mode and vehicle speed above a calibratable value, the
HVAC idle boost request level is constantly calculated. That calculation uses head pressure
cals and the actual head pressure. Once the vehicle drops below a calibratable vehicle
speed, the last calculated HVAC idle boost level is used as the AC request idle boost output.
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Note: For HVAC controls without the capability to receive or transmit serial data, this idle
boost functionality shall be implemented in another ECU, typically the BCM or IP Cluster
ECU.
Lighting
The ECC controls both button and display backlight.
Load shed
The Load Shed feature reduces or eliminates loads controlled by the HVAC system. System
loads are shed in an effort to preserve vehicle battery life.
Parking heater
The Parking Heater module provides heating to the passenger compartment when the
vehicle is in off power mode. It is a fuel operated coolant heater combined with a coolant
pump that circulates warm coolant through the heater core. The park heater can be
activated through a timer or remote key fob.
The Parking Heater module can also be used as an auxiliary heater when the engine is
running.
Passenger temperature control
The HVAC system controls the Passenger temperature based on input from the user or
comfort algorithm. It is also adjusted due to remote start, Park Heater, REST and afterblow.
Rear blower setting
Rear Blower Setting can be controlled through two facets. The driver can deactivate the
rear blower via controls in the front (zone button) and the rear passengers can control the
rear blower via controls in the rear. There are two types of rear controls, one set is a
discrete control and the other is ‘smart’ controls controlling a display.
Rear defog
The Rear Defog Control System utilizes a single zone backlight design, driven with a single
or dual relay (tied to glass breakage feature) configuration. Additionally, up to two outside
rear view mirrors can be heated if required. A switch for the customer to control the system
is provided within the HVAC control head. Also included in the HVAC control head is an
indicator to provide the customer with the current state of the system. The system is only
operational when the ignition switch is in the run position and engine is running or during
remote start.
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Rear air distribution mode
Rear Air Distribution Mode is controlled through either Rear Discrete controls or through
Rear Smart controls. Three modes are available to the rear occupants:
floor
vent
Bi-Level.
Rear temperature control
The HVAC system controls the Rear temperature based on the input from the user or
comfort algorithm. It is also adjusted due to remote start, Park Heater, REST and afterblow.
Regulated voltage control
The HVAC system will request a voltage boost if certain conditions exist. This can happen
due to the current blower state, cooling operations, or rear defog operation.
Remote start
The Remote Vehicle Start function allows the customer to start the vehicle without using the
ignition switch. It also allows starting up the vehicle heating or air conditioning system and
other vehicle systems to provide the customer with a comfortable vehicle when they enter it.
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Connectors and pin assignment ECC
X1…4
The four connectors are polarized. They differ in the position of their nibs and the
connectors’ color. Used colors are:
Pressure suction Sensor
Windscreen Temperature
Air Quality Sensor
PCAT Front
Humidity sensing temp signal
5V Ref. (Sensors)
5V GND (Sensor/Electrical)
Rear Blower Switch Position
Rear Mode Switch Position
Rear Temp Switch position
LSD Spare
Humidity
Sun load: Multi zone/Single zone
Spare Analog 2
Spare Analog 3
GND (option)
DAT 5 Rear Upper (or DAT2 with C68)
DAT 6 Rear Lower
Sun load clocked Supply
BATT
114
mm² Ω
Not connected in Saab 9-5
Not connected in Saab 9-5
Not connected in Saab 9-5
Not connected in Saab 9-5
Not connected in Saab 9-5
Not connected in Saab 9-5
mm²
Pigtail Wire Color
Pigtail Wire Gauge
Terminal Plating
Circuit #
7562
7565
5203
734
3197
597
7566/6102
760
2615
2214
N/A
7564
1783
N/A
N/A
A50
N/C
404
405
590
A40
Shield Group
Cavity
Circuit Description
X1-1
X1-2
X1-3
X1-4
X1-5
X1-6
X1-7
X1-8
X1-9
X1-10
X1-11
X1-12
X1-13
X1-14
X1-15
X1-16
X1-17
X1-18
X1-19
X1-20
X2-1
X4
gray
Twist Group & Rate
X3
black
Max. Wire
Resistance
X2
brown
Minimum Wire Gauge
X1
green
Page 116
X2-2
X2-3
X2-4
X2-5
X2-6
X2-7
X2-8
X2-9
X2-10
X2-11
X2-12
X2-13
X2-14
X2-15
X2-16
X2-17
X2-18
X2-19
X2-20
X3-1
X3-2
X3-3
X3-4
X3-5
X3-6
X3-7
X3-8
X3-9
X3-10
X3-11
X3-12
X3-13
X3-14
X3-15
5060
5060
7531
3196
N/A
3195
A50
A41
7574
7573
204
5127
N/A
754
2211
597
6559 [With RSA
options] and 407
[w/o RSA option]
193
1596 and 3437
516
3167
3165
3168
3166
N/A
N/A
N/A
407
598
3169
3170
3171
3172
7572
GMLAN1
GMLAN2
LIN
Auxiliary Heater Status Signal
(Diagnostics)
LED out (PWM) Spare
Auxiliary Heater Control Signal (LSD
PWM 150Hz only)
GND
IGN
EVDC Compressor Drive LSD PWM
EVDC Compressor VBATT
A/C Low Pressure Sensor Signal
Water pump/After Boil Pump LSD
HSD Spare
Blower Motor Speed Control(LPM front)
Rear Blower Motor Speed Control (LPM)
5V Ref. (Rear switches)
5V GND (Rear switches)
Rear Defog HSD
Water Valve/Thermal EXP HSD // Aero
shutter
DAT 1 front upper left
Actuator - Mode-1 (Control-1)
Actuator - Mode-1 (Control-2)
Actuator - Mode-1 (Control-3)
Actuator - Mode-1 (Control-4)
Actuator - Air Inlet A
Actuator - Air Inlet B
Actuator - Air Inlet (Feedback)
5V Gnd (Front Bi Directional motors,
Evap)
5V Ref (Front Bi Directional motors,
Evap)
Actuator Temp-1 (Control-1)
Actuator Temp-1 (Control-2)
Actuator Temp-1 ( Control-3)
Actuator Temp-1 (Control-4)
Stepper Signal-Front
115
Not connected in Saab 9-5
Not connected in Saab 9-5
Not connected in Saab 9-5
Not connected in Saab 9-5
Not connected in Saab 9-5
Not connected in Saab 9-5
Not connected in Saab 9-5
mm²
Pigtail Wire Color
Pigtail Wire Gauge
Terminal Plating
Ω
Shield Group
Max. Wire
Resistance
mm²
Twist Group & Rate
Minimum Wire Gauge
Cavity
Circuit #
Circuit Description
Page 117
X3-16
X3-17
X3-18
X3-19
X3-20
X4-1
X4-2
X4-3
X4-4
X4-5
X4-6
X4-7
X4-8
X4-9
X4-10
X4-11
3173
3174
3175
3176
6137
3177
3178
3179
3180
3181
3182
3183
3184
517
7572
X4-12
X4-13
X4-14
X4-15
X4-16
X4-17
X4-18
X4-19
X4-20
520
3185
3186
3187
3188
3189
3190
3191
3192
518
Actuator Air Inlet-1 (Control-1)
Actuator Air Inlet-1 (Control-2)
Actuator Air Inlet-1 ( Control-3)
Actuator Air Inlet-1 (Control-4)
EVAP Core Temp
Actuator - Mode-2 (Control-1)
Actuator - Mode-2 (Control-2)
Actuator - Mode-2 (Control-3)
Actuator - Mode-2 (Control-4)
Actuator - Temp-2 (Control-1)
Actuator - Temp-2 (Control-2)
Actuator - Temp-2 (Control-3)
Actuator - Temp-2 (Control-4)
DAT3 - Front Upper Right (Pass)
Stepper Signal-Rear
DAT2 - Front Lower Left (Driver)
(Connected to X1 with C68)
DAT4 - Front Lower Right (Pass)
Actuator - Mode-3 rear (Control-1)
Actuator - Mode-3 rear (Control-2)
Actuator - Mode-3 rear (Control-3)
Actuator - Mode-3 rear (Control-4)
Actuator -Temp-3 rear (Control-1)
Actuator - Temp-3 rear (Control-2)
Actuator -Temp-3 rear (Control-3)
Actuator -Temp-3 rear (Control-4)
116
mm²
Pigtail Wire Color
Pigtail Wire Gauge
Terminal Plating
Ω
Shield Group
Max. Wire
Resistance
mm²
Twist Group & Rate
Minimum Wire Gauge
Cavity
Circuit #
Circuit Description
Page 118
EHS (Electrical Heater System)
The Electrical Heater System provides an auxiliary heater installed in the ventilation unit. Its
purpose is to heat up the air flowing into passenger compartment while the engine is still
heating up and not providing enough heated air.
co
re
He
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Sw
Po
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Po
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W
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Block diagram EHS
Functional description EHS
The Electric Heater System is controlled by the HVAC
silverbox. It gets a PWM signal from ECC. EHS needs
some requirements to be fulfilled to work. Otherwise the
device will be disabled.
The requirements are:
• Outside Air Temperature <11°C
• Coolant Temperature <75°C
• Ignition “on”
• Engine Running “on”
• Engine Speed >500 rpm
• Engine Running Time <1h
• Battery Voltage between 9.2 and 16.1 V
• Temperature Mix Flap > 90% open
If all requirements are fulfilled, EHS is in “forced mode”, which means that PWM signal has
100% duty cycle
In some cases, the PWM signal which powers the EHS will be reduced to a value lower than
95%. This is the so called controlled mode. Possible values to reduce PWM cycle are:
• battery state of charge sinks below 60%
• battery state of charge critically low bit is set
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Page 119
• battery load shedding level not 0 (level 1 – 80%, level 2 – 50%, level 3 – off)
118
Page 120
Connectors and pin assignment EHS
X1
(signal)
Auxiliary Heater Status Signal
Battery
Ground
119
Pigtail Wire Color
3196
A39
A50
Pigtail Wire Gauge
Auxiliary Heater Control (PWM-signal)
Battery Positive Voltage
Terminal Plating
3195
A39
Shield Group
X1-1
X1-2
X1-3
X1-4
X2-1
X2-2
Twist Group & Rate
Circuit #
Circuit Description
Max. Wire
Resistance
Cavity
Minimum Wire
Gauge
X2
(power)