1997 ASTON MARTIN DB7 key

Air Conditioning
Lower Feedback Potentiomenter "3^^?
Blower Motors Potentiometers
The air conditioning system has two blower motors

(Fig.
1
-7) that operate together to maintain the flow
of air into the car at the desired
level.
The motors are
supplied from an ignition switched supply through
transistorised control circuits fitted in the motor
outlets. The circuits steplessly vary the speed of the
motors at
1
and 2 selections of the mode switch and
operate the motors to high speed when 3
is
selected.
The electronic components are assembled on a
heat sink and include a power transistor (Fig.
1
-9)
and feedback diode (Fig. 1-8). The switches are
supplied and controlled by the ECM.
When the mode switch is set to 3, the high speed
relay (Fig. 1-10) is energised from pin 16 of the

ECM,
opening
a
path to earth-ground, and allowing
full battery voltage to be applied to the motor. At 1
and 2, the motor is supplied with a continuously
variable voltage by the power transistor and the
earth-ground return is made via the ECM. The
feedback diode enables the ECM to sense the
voltage at the negative terminal of the blower
motor.
Lower Feedback Potentiometer
The lower feedback potentiometer determines the
position of the lower blend flap in the air
conditioning unit and feeds this information to the

ECM.
The ECM is thereby able to command the
lower flap servo motor to move the flap to a new
position and maintain the temperature of the air to
the feet and rear outlets at the desired level.
V 1
• 2
V3
Figure 1.
Key to Fig. 1

1.
Output signal from Pin 16 ECM

2.
Power feed
3. Blower feedback
Left hand Pin 22, Right hand 33

4.
Blower output Left Pin 31, Right 32
5. Control switch earth-ground
6. ECM earth-ground Pin 45
7. Blower motor
8. Feedback diode
9. Power transistor

10.
High speed relay
Figure 1.

1.

2.

3.
+5 volts from ECM Pin 43
Feedback signal to ECM Pin 29
Earth-Ground
The potentiometer is supplied with +5V from pin
43 of the ECM and returns its feedback signal via
pin 29. The feedback signal is 10OmV (COLD AIR)
to 1.2 V (HOT A!
R).
The potentiometer also provides
a single feedback signal of 2.9V when the blend
flap is in DEFROST. In this position, the feet and
rear outlets are closed and all air is directed to the

screen.

8-26 May 1996

Air Conditioning
Vacuum System •^^
Vacuum System The flaps in the cabin air distribution vents and the
water valve in the pipeline from the engine coolant
system to the heater matrix are all operated by
vacuum actuators. The vacuum forthese
is
supplied
by four solenoids mounted in pairs behind the front
footwell outlets. Each solenoid and its associated
pipe work is identified by a colour:
Defrost
Auto Re-circulation
Water valve
Centre vent
Green
Blue
Red
Black.
The vacuum supply pipes to the re-circulation and
centre vent actuators are fitted with restrictors in
order to slow down the operation of the flaps and
avoid hunting. The re-circulation flaps can take up
to 30 seconds to move to a new position.
Vacuum is piped to the solenoids from the engine
manifold through a reservoir. The solenoids are
energised by signals from the ECM in response to
demand ,sensing and feedback signals.
-T^^^T 2
3
figure 7.
Key

1.

2.

3.

4.

5.
6.
7.
8.
9.

10.

11.

12.

13.

14.

to Fig. 1
Vacuum reservoir
Defrost solenoid
Defrost-demist actuator
Restrictors
Centre vent solenoid
Centre vent actuator
Defrost vacuum pipe
Centre vent vacuum pipe
Recirc. solenoid
Recirc actuator
Recirc. vacuum pipe
Water valve solenoid
Water valve actuator
Water valve vacuum pipe
Figure 2.
5
7
10
Key to Fig. 2

1.
Defrost (Green) solenoid

2.
+12V Defrost Input from ECM pin 12
3. Defrost output to ECM Pin 11

4.
Recirc (Blue) solenoid
5. +12V Recirc. input from ECM Pin 3
6. Water valve (Red) solenoid
7. +12V Water valve input from ECM Pin
1
7
8. Centre vent (Black) solenoid.
9. +12V Centre vent input from ECM Pin 18

10.
ECM earth-ground
8-28 May 1996

'^T?
Air Conditioning
Compressors
Compressors
Compressor Clutch Control
The compressor
pu I
ley
is
driven continuously when
the engine is running. An electromagnetic clutch
allows the compressortobeengagedordisengaged.
The clutch is energised by battery supply voltage
when the clutch relay RF3 is closed by a signal from
the ECM (pin 21) via the engine management

system.

6^
o>o 1
4
Figure 1
Figure 2
Key to Fig. 2

1.

2.

3.

4.

5.
Condenser
Clutch relay supply
Compressor clutch
HSLP switch
Protection diode
Earth-ground
Key to Fig. 1

1.
+ve battery supply

2.
Clutch relay
3. Compressor clutch

4.
Pin 20 ECM supply to clutch relay solenoid
5. Earth-Ground
6. Earth-Ground
Trinary Switch
High Side Low Pressure Switch
The high side low pressure switch (HSLP) is
connected in the earth-ground return lead of the
compressor clutch
coil.
The switch is a function of
the trinary switch and monitors the pressure on the
high side of the refrigeration system. If the pressure
drops below 25 psi (+ 5 psi) the contacts open to de-
energise the clutch coil and disengage the clutch.
Low pressure occurs when there is a fault in the

system,
and the HSLP switch contacts remain open
until the fault has been rectified.
The condenser (Fig, 3) consists of a refrigerant coil
mounted in a series of thin cooling fins to provide
maximum heat transfer in the minimum amount of

space.
It is mounted directly behind the car radiator
and receives the fu
11
flow of ram air induced by the
forward motion of the car and the suction of the
cool ing
fan.
Refrigerant enters the inlet at the top of
the condenser as a high pressure hot vapour. As the
vapour passes down through the condenser coils
cooled by ram air, a large quantity of heat is
transferred to the outside air and the refrigerant
changes to a high pressure warm liquid.
May 1996 8-35

^?
Air Conditioning
Sanden Compressor SD7H15
Sanden Compressor SD7H15
The Sanden SD7H15 compressor
is a 7
cylinder
machine with
a
bore
of
29.3
mm (1.15 in) and a

stroke
of
32.8
mm (1.29
inches).
The displacement
per
revolution
is
155cc
(9.5

cubic inches).
The magnetic clutch
is
engineered with
the

compressor
as a
complete assembly resulting
in a

relatively small unit
of
lightweight construction.
The compressor may be mounted up to 90° from
its

upright position.
The compressor incorporates
a
lubrication system
which reduces the
oil
circulation ratio
to a
level
of

less than
2% at 1800 rpm.

An
oil
deflector
and
positive pressure differential
lubrication system promotes oiling
to the
cylinder

wall,
piston
rod
assemblies, main bearings
and

shaft
seal,
and
ensures that
oil
circulation
to the

refrigeration circuit
is
kept
to a
minimum.
The

compressor ischarged
with!
35 cc(4.6fluid ounces)
ofSunico NoSGSoil at the factory. Only this oil
or

oneoftheequivalentoilsdetailed below should
be

used.

Key

1.

2.

3.
4.
5.
6.
7.
8.

9.
10.

11.

12.
13.
14.
15.
16.

to Fig. 2.
Service port
Cylinder head
Hose connection
Anti-rotation gear
Oil filler plug
Planet plate
Clutch bearing
Electromagnetic clutch
Valve plate assembly
Cylinder and valve plate gasket
Cylinder block
Piston
Cam rotor
Needle thrust bearing
Front housing and 'O' ring
Shaft seal
Compressor Oils
Suni
CO
No 5GS
Texaco Capella E
Virginia Chemicals 500 Viscosity

13
14 15 16

Figure
2.

May
1996
8-37

Air Conditioning
Refrigerant Recovery and Recycling ^=2?
Recovery Procedure
Hote:
Run the
air-conditioning
system
for
a
few
minutes
before starting the
recovery
procedure as
this will
enable

more refrigerant to be recovered. Turn the
system
off
before
starting
the procedure.

1.
Attach the red (high side) hose oftheunittothe high
side fitting of the system on the vehicle then fit the
blue (low side) fitting to the low side on the vehicle.
Note: Make sure that the Air conditioning
system
has
pressure in it before beginning the recovery
process;
if
there is no
system
pressure there is no refrigerant to

recover.
Also
make sure that the
oil
drain
valve
is
closed.

2. Open both the high and low side valves on the
control panel.
3. Open the red CAS (vapour) valve and the blue
LIQUID valve on the tank.

4.
Turn on the MAIN POWER switch.
5. Press the RECOVERY key on the key-pad. The
display shows that the unit in the RECOVER mode
and AUTOMATIC cycle. After the compressor starts
the display shows the weight of refrigerant being

recovered.
The compressor shuts off automatically
when the recovery is complete and the display
shows the message 'CPL' and the final weight of the
recovered refrigerant.
6. Wait for five minutes and watch the manifold
gauges for a rise above 0. If a rise occurs press the
HOLD/CONT key. Repeat as needed until the
system pressure holds for two minutes.
Note: Drain the oil
separator
after
each
job.
7. Slowly open the oil drain valve and drain the oil
into the oil catch bottle. When all the recovered oil
has completely drained close the valve.
8. Replace oil lost during the recovery procedure by
measuringthe amount of oil inthe catch bottle and
adding the same amount of new oil to the system.
Note:
Dispose
of the
recovered
oil in an approved way.
9. When the recovery tank is full the compressor is
shut off and the display shows the message FULL.
Evacuating and Recycling the Refrigerant

1.
Open the red (high side) and the blue (low side)
valves on the unit and open the red GAS (vapour)
valve and the blue LIQUID valve on the tank.

2.
Enter the required time using the key-pad, press
enter,thedisplayshowstheenteredtime in minutes.
3. Start the vacuum pump by pressing the VACUUM
KEY again. The recycling process begins
approximately five seconds after the vacuum pump
starts and the message RECYCLE is displayed.
Note: If the vacuum pump
has
run for ten hours or
over

without an oil change the
message
OIL
flashes
on the
display.
Change
the pump oil and
then press
the
SHIFT/

RESET key and
the
zero key to
reset the
oil
change
timer
to zero.
The digital display counts down the evacuation

time.

4.
Check for non-condensibles after five minutes

recycling.
Ifthegauge needles are more than lOpsi
apart purge the non-condensibles from the tank by
open
i ng
the purge valve on the back of the
un
it and
continue to bleed until both needles show the same

reading.

The vacuum sequence continues until the
programmed time has elapsed at which point the
message CPL is displayed.
5. If the moisture indicator turns green recharge with
refrigerant.
or
5. If the moisture indicator has not turned green
replace the unit's filter-drier, which is probably

saturated.

Note:
Pressing
any key at this point allows the next
function to be
accessed.

To recycle the refrigerant only without pulling a
vacuum for an indefinite period of time press the
SHIFT/RESET key and the RECYCLE key on the key­

pad.
Press the SHIFT/RESET key to cancel.
For vacuum only press the SHIFT/RESET key and
the ENTER key and then press
"1".
Run the vacuum
pump as long as required and then press
"1"
or
press SHIFT/RESET to cancel.
8-48 May 1996

^2?
Air Conditioning
System Recharging / Compressor Oil Check
Recharging the System

1.
Open the high side valve on the unit control panel.
If the messages PROGRAM and CHARGE are not
displayed press the CHG key to enter PROGRAM

mode.

2.
Key in the amount of refrigerant needed to recharge
the system and press ENTER.
3. Press the CHG key; the message AUTOMATIC and
the entered amount of refrigerant wi
11
be displayed.
The display counts down to zero as the charging
process proceeds. When the charging is complete
the message CPL is displayed.
If the refrigerant transfer is too slow the charging
unit emits a signal. If the message CHECK
REFRIGERANT is not displayed, close the high side

valve,
open the low side valve and start the air
conditioning system to pull the remainder of the
charge into the system.
If the refrigerant transfer will not complete and the
message CHECK REFRIGERANT is displayed, press
the HOLD/CONT key to interrupt the cycle then
reset the unit by pressing the RESET key. Recover
the refrigerant already charged into the system by
following the procedure for recovering the
refrigerant, add new refrigerant to the tank and
return to Step 1 to recharge the system.

4.
If the air conditioning system is not running start it
and let it run until the gauge pressure readings
stabilize (compare the gauge readings with the
system manufacturer's specifications).
Note:
Ensure
that the
readings
are accurate by closing
both the high and low side
valves
on the unit's control
panel.
5. Check the evaporator outlet temperature to make
sure that the air conditioning system is operating
properly (refer to the system manufacturer's
specifications for the proper temperature).
Compressor Oil Checic
Data
Special Tools
Sanden oil dipstick JD 149
Torque Figures
Oil filler plug 8-12 Nm
Procedure
Whenever a component has been replaced in the
refrigerator system or there is an obvious oil leak, the
following procedure should be carried out.
A Sanden oil dipstick and angle gauge are required in
order to carry out the check.

1.
Run the compressor for 10 minutes at engine idle

speed.

2.
Depressurise the system.
3. Lay the angle gauge across the flat surfaces of the
two front mounting lobes. Centre the bubble and
note the mounting angle.

4.
Remove the compressor from the vehicle.
3. Remove the plug from the oil filler hole
(1
Fig. 1).

4.
Rotate the counter weight (3 Fig. 1) on the front of
theclutchtoallowthedipstick(2 Fig. 1)to penetrate
to its fullest extent.
Figure 1.
5. Insert the dipstick to its stop position (4 Fig. 1). The
point of dipstick angle should be facing left.
6. Removethedipstickandchecktheoil levelagainst
the figures quoted in the chart below.
May 1996 8-49

Air Conditioning Repair Procedures
Blower Assembly Renewal o^s^-^?

12.
Disconnect the vacuum pipe from the flap actuator

(Fig.
1-4).

13.
Open the re-circulation flap in the base of the
blower assembly and fit a wedge to retain it in the
open position (Fig. 1-5).

14.
Remove the bolts securing the blower assembly
and ease the blower unit from its location (Fig.
1
-6).

15.
Remove the tape securing the ducting to the
assembly and remove the ducting (Fig.
1
-7).
Note: To remove the blower motor
assembly
from the
vehicle,
the
lower flap must be opened to allow the upper
flap to
disengage
from the upper body
aperture.

8.2.10.1 Blower Assembly Driver/
Passenger Side Overhaul

Note:
Blower
assemblies
under warranty must not be
dismantled.

1.
Remove the three selftapping screws
(Fig.
1-1) from
the air intake casing.
Figure 7.

2.
Part the air intake casing (Fig.
1
-2) from the motor
assembly (Fig. 1-2) and disconnect the electrical
connections at the lucar connectors (Fig.
1
-4).
Note: Mark the position of the
various components
with
paint or
a
scriber.
This
facilitates
re-assembly.

3. One lucar connector has a raised projection which
matches the aperture in the motor casing to ensure
that the connections are replaced correctly and that
the rotation of the motor is unaffected.

4.
Remove the bolts securing the motor mounting
bracket to the fan housing (Fig. 1-5).
5. Remove the motor and fan assembly from the fan

housing.

6. Remove the mounting bracket from the motor.
7. Using appropriate Allen key, remove the impellor
fan from the spindle.
Re-assembling

1.
Refit the fan to the motor and secure it to the
spindle.

2.
Refit the mounting bracket tot he motor.
3. Locate the fan and mounting assembly into the fan

housing.

8-60 May 1996

'=^
The Aston Martin Lagonda Diagnostic System
Installation Instructions
12 10
19 22 21 20
VIA A / /^^>^ I B T
A-XA^I'A® QA
13
16
18 29
Figure 7. The Aston Martin Diagnostic System
Key to Figure 1

1.

2.

3.

4.

5.
6.
7.

7.1.

7.2.
7.3.
7.4.
7.5.
7.6.
7.7.
8.
9.

10.

11.

LCD touch screen
Power on switch
Power off switch
Screen contrast control
Battery charge indicator (Orange/Yellow)
Power on indicator (Green)
PDU interface connectors
Black probe
Red probe
Current clamp
Pressure transducer
Vehicle battery adaptor (VBA)
VIA, base station, serial interface and system test
Temperature probe
Battery cover
Connector A for vehicle cable
VIA power input cable
Connector B for vehicle cable

12.

13.

14.

15.

16.

17.

18.
19.

20.

21.

22.

23.

24.

25.

26.

27.

28.
29.

Connector for PDU cable
VIA status indicator
Vehicle Interface Adaptor (VIA)
Portable Diagnostic Unit (PDU)
Base Station
Base station door
Base station door lock
Charging and loading data connector
Secondary charging connector
Power on indicator (Green)
Status Indicator (Red)
CD-ROM drive
Electronic module securing screws
CD-ROM eject button
CD-ROM drive active light
Audio output (not used)
Audio level (not used)
Base station drawer.
May 1996 9-3