1997 ASTON MARTIN DB7 water valve

Electrics
Electrical Component Location Index - Up to 97 MY
Component Name
Seat Belt Switch
Seat ECU - Driver
Seat ECU - Passenger
Seat Heater - Cushion Element
Seat Heater - Squab Element
Seat Heater Control Module
Seat Motor Potentiometer
Seat Pressure Pad
Seat Switch Pack - Driver
Seat Switch Pack - Passenger
Security System Aerial
Security System ECU
Side Marker Lamp - LH Front
Side Marker Lamp - RH Front
Speaker - Rear LH
Speaker - Rear RH
Speed Control Dump Valve
Start Inhibit Switch
Starter Motor Solenoid
Stop Lamp Fail
Stop Lamp/Cruise Disable Switch
Thermal Breaker - Window Lift
Throttle Potentiometer
Water Temp Sensor - Engine ECU
Water Temp Sensor - Temp Gauge
Wheel Speed Sensor - Front RH
Wheel Speed Sensor - Front LH
Wheel Speed Sensor - Rear RH
Wheel Speed Sensor - Rear LH
Window ECU - LH
Window ECU - RH
Window Switch - RH
Window Switch LH
Wiper Logic Module
Wiper Motor
Window Lift Motor
Location
Reference
13-2
6-2
6-2
12-5
12-4
6-3
9-7
12-6
6-8
6-8
2-12
15-2
5-5
5-5
6-10
6-10
1-4
10-9
3-14
15-10
11-8
4-7
3-15
3-5
3-4
13-4
13-4
13-1
13-1
12-11
12-11
2-5
2-5
4-5
1-1
12-10
Wiring Diag.
Reference
22-A3
16-A1
15-A1
22-A2
15/16-A4
22-A5
22-C2
22-D3
16-B1
15-B1
24-C2
26-B6
1-C2
1-A3
24-B2
24-C2
2-A2
21-C3
3-C2
25-A3
12-C5
9-C3
5-A3
5-C2
5-C2
29-C3
28-D4
28-D3
28-D2
17-D3
18-D3
19-A2
19-D2
9-A3
8-C3

Rep.
Op.
Reference

6.6.16.1
6.6.17.1

6.6.17.2

6.6.18.1

6.6.18.2

6.6.18.3

6.6.19.1
6.6.20.1
6.6.21.1
6.6.21.1
6.6.22.1

6.6.22.3

6.1.18.1
6.1.18.1
6.6.23.1
6.6.23.1
6.1.19.1
6.1.20.1

6.3.02.2

6.9.15.1
6.4.02.1
6.1.21.1

2.5.02.2

6.3.07.1

8.2.12.1

5.1.12.1
5.1.12.1
5.2.01.1
5.2.01.1

6.1.22.1
6.1.22.1
6.5.03.1
6.5.03.1
6.2.01.1

6.1.21.3

Notes
6-22 May 1996

Air Conditioning
Contents '=2?
System Fault Diagnosis
Fault Finding
Blower Motor Test
Open Water Temperature Switch Needs
Short Water Temperature Switch Leads
Refrigeration
Compressors
Compressor Clutch Control
Trinary Switch
Condenser
Receiver-Drier
Evaporator
Expansion Valve
Sanden Compressor SD7H15
Manifold Gauge Set
System Checking with the Manifold Gauge Set
Evacuating the Manifold Gauge Set
Connecting the Manifold Gauge Set
Stabilising the System
Purging the Test Hoses
Leak Test
Manifold Gauge Set Check Procedures
Refrigerant Slightly Low.
Refrigerant Excessively Low.
Air In The System.
Compressor Malfunction
Moisture in the System
A Large Amount of Air in the System.
Expansion Valve Malfunction.
Expansion Valve Malfunction
Restriction in the High Pressure Side.
Torque Levels for the Hose Connections
8-30
8-33
8-33
8-33
8-34
8-35
8-35
8-35
8-35
8-36
8-36
8-36
8-37
8-39
8-39
8-39
8-39
8-40
8-40
8-41
8-41
8-42
8-42
8-43
8-44
8-45
8-45
8-46
8-46
8-47
Air Conditioning Procedures
Depressurising
Recovering Refrigerant
Evacuating and Recycling the Refrigerant
Recharging the System
Compressor Oil Check
8-47
8-47
8-48
8-49
8-49
8-2 May 1996

^7
Air Conditioning
Contents
Repair Procedures
8.1.01.1 Compressor Removal/Renewal 8-51
8.1.02.1 Field Coil Renewal 8-52
8.1.03.1 Renew Gasket Kit 8-52
8.1.04.1 Valve Plate Renewal 8-53
8.1.05.1 Expansion Valve Renewal 8-54
8.1.06.1 Hose-Compressor to Evaporator Renewal 8-55
8.2.01.1 Air Conditioning Unit Renewal 8-55
8.2.02.1 Evaporator Unit Renewal 8-56
8.2.03.1 Upper Servo Feedback Potentiometer Renewal 8-57
8.2.04.1 Lower Servo Feedback Potentiometer Renew 8-57
8.2.05.1 Upper Flap Motor Assembly Renew 8-58
8.2.06.1 Lower Flap Motor Assembly Renew 8-58
8.2.07.1 Ambient Temperature Sensor Renew 8-59
8.2.08.1 Blower Motor Driver Side Renewal 8-59
8.2.09.1 Blower Motor Passenger Side Renewal 8-59
8.2.10.1 Blower Assembly Driver/Passenger Side Overhaul 8-60
8.2.11.1 Blower Motor High Speed Relay Renewal 8-61
8.2.12.1 Water Temperature Switch Renewal 8-62
8.2.13.1 Heater Matrix Renewal 8-62
8.2.14.1 Electronic Control Module Renew 8-63
8.3.01.1 Vacuum System Solenoid Renewal 8-63
May 1996 8-3

^^?
Air Conditioning
System Description
System Description
The in-car temperature and humidity are regulated by the electronically controlled air conditioning system. The
system comprises four subsystems:
• heater matrix, supplied with water from the engine cooling system
• refrigeration
• vacuum
• electronic control
Apart from the ambient temperature sensor and the aspirated in-car temperature sensor, most of the components
are housed in the air conditioning unit (Fig. 1) situated behind the dash board, or in the engine compartment.
Figure 1.
Key to Fig. 1 - Left Hand Air Conditioning Unit

1.
Upper feedback potentiometer

2.
Water temperature switch
3. Lower feedback potentiometer

4.
Vacuum valve block
5. Vacuum restrictor
6. Condensate drain tube
Figure 2.
Key to Fig. 2 - Right Hand Air Conditioning Unit

1.
Upper servo motor

2.
Electronic control module
3. Lower servo motor

4.
Evaporator sensor
5. Condensate drain tube
Special Servicing Tools and Equipment
1 PDU system
1 Charging station
1 Leak detector
1 Temperature test box
1 Sanden compressor service tool kit
1 CM Type compressor service tool kit
1 Digital voltmeter
1 Multimeter
May 1996 8-7

Air Conditioning
Working Practices O" 15-^?
Working Practices
General
Be aware of, and comply
with,
all health and safety
requirements.
Before beginning any repair or service procedure,
disconnect the vehicle battery ground connection
and protect the vehicle from dirt or damage.
Work in a well ventilated, clean and tidy area.
Recovery and chargeequipment must comply
with,

or exceed the standard detailed in the General
Description.
Handling Refrigerant
Wear eye protection at all times.
Use gloves, keep skin that may come into contact
with refrigerant covered. If the refrigerant comes
into contactwith youreyesorskin wash the affected
area immediatelyw'ith cool water and seek medical
advice, do not attempt to treat yourself.
Avoid inhaling refrigerant vapour, it wil
your respiratory system.
irritate
Never use high pressure compressed air to flush out
a system. Under certain circumstances a
combination of HFC 134A and compressed air in
the presenceofa source ofcombustion (for instance,
welding or brazing equipment), results in an
explosion that releases toxic compounds into the
atmosphere.
The refrigerant and CFC 12 must never come into
contact with each other
as
they form an inseparable
mixture that can only be disposed of by incineration.
Do not vent refrigerant directly into the atmosphere,
always use approved recovery equipment.
Refrigerant is costly but it can be recycled. Clean
the refrigerant, using the recovery equipment and
reuse it.
Carry out LeakTestsonly with an electronic analyser
dedicated to Refrigerant El 34A.
Do not attemptto guess the amount of refrigerant in
a system, always recover it and recharge with the
correct charge weight. Do not depress the charge or
discharge port valves to check for the presence of
refrigerant.
Handling Lubricating Oil
Avoid breathinglubricantmist,itwillcauseirritation
to your respiratory system.
Always decant fresh oil from a sealed container. Do
not leave oil exposed to the atmosphere for any
reason other than to fill or empty a system; PAG oil
is hygroscopic (it absorbs water) and iscontaminated
rapidly by atmospheric moisture.
Following the recovery cycle do not reuse the oil
when it has been separated from the refrigerant;
dispose of the oil safely.
System Maintenance
Do not leave the system open to the atmosphere. If
a unit or part of the system is left open for more than
five minutes, it is advisable to renew the receiver-
dryer. There is not a safe period in which work is to
be carried out. Always plug pipes and units
immediately after disconnection and only remove
plugs when re-connecting.
If replacement parts are supplied without transit
plugs and seals do not use the parts. Return them to
your supplier.
Diagnostic equipment for pressure, mass and
volumeshouidbecalibrated regularly and certified
by a third party organisation.
Use extreme care when handling and securing
aluminium fittings, always use a backing spanner
and take special care when handlingtheevaporator.
Use only the correct or recommended tools for the
job and apply the manufacturer's torque
specifications.
Keep the working area, all components and tools

clean.

8-8 May 1996

Air Conditioning
Functional Check
Functional Check
This functional check procedure is provided as a simple system validation and is structured to augment the Portable
Diagnostic Unit (PDU).
Stage 1 (Cold engine only, if not proceed to Stage 2)
Procedure Normal System Reaction

1.
Ignition ON
Select MIN temperature, MAN, speed 3, Mid face.
(Engine Stationary) Fans Start

2.
Select MAX temperature Fans continue to run
3. Ignition OFF
Select MAX temperature and defrost
Ignition ON Fans start at maximum speed

4.
Select fan speed
1
Fan speed adjusts accordingly - system OK
Stage 2
Procedure Normal System Reaction

1.
Start up engine and warm up
Select fan speed 1, MAN, MAX TEMPERATURE
and mid face

2.
Open all vents Fans start after 3 seconds

2.
Select fan speed 2 Fan speed increases then stabilises
3. Select fan speed 3 Fan speed increases then stabilises

4.
Select defrost Fan speed steady at high
All air at screen and dash end
5. Re-select fan speed 1
Select AUX ignition key position
6. Slowly select MIN temperature Solenoids switch 1. centre vent

2.
water valve
3. Re-circulation
7. Re-select MID temperature
8. Select DEM Solenoid clicks
Air at screen
9. Select manual re-circulation Solenoid click

10.
Check flap for position

11.
Run Engine to normal temperature

12.
Select: MAN, 3/4 MAX heat and fan speed 2 Air from door vents
cool,

air temp from foot outlet slightly warm

13.
Select MAX temperature and air differential to hot face All vent outlets max temp except screen vent

14.
Select temperature
approx. 1/4 MAX heat and mid face level Cool air from centre vents

15.
Select MIN temperature Blower flaps at re-circulation position
All outlets blowing cold air except screen vent
May 1996 8-15

Air Conditioning
/J=y>f^^^
—p )
System Trouble Shooting

12.
Compressor clutch slipping.

13.
Blower flaps or distribution vents closed or partially seized.

14.
Water valve not closed.

15.
Evaporator sensor detached from evaporator.
Intermittent Cooling
Is the electrical circuit to the compressor clutch consistent?

2.
Is the electrical circuit to the blower motor(s) consistent?
3. Compressor clutch slipping.

4.
Faulty air distribution flap potentiometer or motor.
5. Motorised in-car aspirator or evaporator temperature sensor faulty, causing temperature variations.
6. Blocked or partially restricted evaporator or condenser.
Noisy System

1.
Loose or damaged compressor drive belt.

2.
Loose or damaged compressor mountings.
3. Compressor oil level low, look for evidence of leakage.

4.
Compressor damage caused by low oil level or internal debris.
5. Blower(s) motor(s) noisy.
6. Excessive refrigerant charge, witnessed by vibration and 'thumping' in the high pressure line (may be indicated by
high HIGH & high LOW side pressures).
7. Low refrigerant charge causing 'hissing' at the expansion valve (may be indicated by low HIGH side pressure).
8. Excessive moisture in the system causing expansion valve noise.

Note;
Electrical faults
may
be more rapidly traced using PDU.
Insufficient Heating

1.
Water valve stuck in the closed position.

2.
Motorised in-car aspirator seized.
3. Blend flaps stuck or seized.

4.
Blocked or restricted blower inlet or outlet.
5. Low coolant level.
6. Blower fan speed low.
7. Coolant thermostat faulty or seized open.
8-18 May 1996

^2?
Air Conditioning
Electronic Control Module
Electronic Control Module (ECM)
The Electronic Control Module (ECM) is located on the right hand side of the heater unit.
The ECM has a digital microprocessor that allows the air conditioning system to maintain the selected in-car
conditions. To do this it compares the signals from the in-car controls with those it receives from the system
temperature sensors and feedback
devices.
On the basis of these comparisons it makes appropriate voltage changes
to vary the blower motor
speed,
flap position and the state of other solenoids that effect the selected temperature

demand.

The ECM is a non-serviceable component but may be interrogated for system
testing.
Care must be exercised when
connecting
the test
equipment
as the ECM
may
be
irreparably
damaged
should any ofthe
test
pins
be
shorted or bent.
20 21 22 23
Q
A / A \/
Em
10 11

1.
Electronic control module (ECM)

2.
Differential temperature control
3. Temperature control

4.
Fan speed control
5. Ambient temperature sensor
6. Motorised in-car aspirator
7. Evaporator temperature sensor
8. Coolant temperature switch
9. Lower flap feedback potentiometer

10.
Upper flap feed back potentiometer

11.
Left hand blower motor feedback

12.
Right hand blower motor feedback

13.
High speed relay

14.
High speed relay

15.
Compressor clutch

16.
Blower motor

17.
Blower motor

18.
Lower flap servo motor

19.
LIpper flap servo motor

20.
Defrost vacuum solenoid

21.
Auto re-circulation vacuum solenoid

22.
Centre vent vacuum solenoid

23.
Water valve vacuum solenoid

24.
Air conditioning function switch
May 1996 8-19