1997 ASTON MARTIN DB7 clutch

Air Conditioning
System Fault Diagnosis D^
Mode Switch: Low or Medium Temperature Demand Switch: Mid-Range - Function Switch: AC
10 to 12V
0 to SOOmV
2.875 to 2.895V
0 to 500mV
0 to 500mV
0.6 to 0.9V
1.15 to 1.45V
260 to 460mV
4.5 to 5.5V
0 to 500mV
10.3 to 13.3V
10 to 13V
10 to 13V
0 to 0.5V
0 to 0.5V
0 to 500mV
0 to SOOmV
Recirc. input
Recirc. output
Reference voltage
Defrost output
High speed relays
Lower feedback pot.
Upper feedback pot.
Water temp, switch engine cold
Water temp, switch engine hot
Defrost output
Clutch output- evaporator
above 2.745 V
Right hand Blower feedback
Left hand Blower feedback
Right hand Blower control
Left hand Blower control
Water valve solenoid
Centre vent solenoid
9
3
7
11
16
29
30
21
21
11
20
33
22
32
31
17
18
Mode Switch: (Auto) Low Temperature Demand Switch: Minimum
Face Level to mid-range 28 1.43 to 1.45V
Servo Motors Stopped
Servo motor lower flap 37 0 to 40mV
Servo motor lower flap 41 0 to 40mV
Servo motor upper flap 40 0 to 40mV
Servo motor upper flap 42 0 to 40mV
Lower feedback pot. 29 0 to 0.2V
Upper feedback pot. 30 0 to 0.2V
Mode Switch: Low Temperature Demand Switch: Mid-Position - Function Switch: AC
Temperature demand 35 1.43 to 1.45V
Servo Motors Stopped
Servo motor lower flap 37 0 to 40mV
Servo motor lower flap 41 0 to 40mV
Servo motor upper flap 40 0 to 40mV
Servo motor upper flap 42 0 to 40mV
Lower feedback pot. 29 0.57 to 0.87V
Upper feedback pot. 30 0.6 to 0.9V
Mode Switch: Low Temperature Demand Switch: Maximum - Function Switch: AC
Temp demand 35 2.665 to 3.105V
Lower flap feedback pot 29
Upper flap feedback pot. 30
0.979 to
1.279V

1.518 to 1.9V
Mode Switch: (Auto) Face Level: Cold Face
Differential temp. 28
Lower flap feedback pot. 29
Upper flap feedback pot. 30
2.665 to 3.105V
0.979 to
1.279V

1.340 to
1.640V

8-32 May 1996

^7?
Air Conditioning
System Fault Diagnosis
Blower Motor Test
Face Level: Hot Face Temperature Demand Switch: Minimum
Differential temp. 28 0 to 200mV
Temperature demand 35 0 to 200mV

Hote:
Allow
the servo motors
to
come to rest before checking voltage
levels.
Typical figures are given
in
brackets.

Mode Switch
Position
Low
Med
High
RH Control
Pin No. 32
1 - 2V (1.77V)
3V (2.28V)
2v
(1.1
7V)
Set Face Differential Pot. to Mid Point
Mode Switch RH Control
Position Pin No. 32
Low 1 - 2V (1.24V)
Medium 1 - 2V (1.4V)
High 2-3V(2.2V)
Set Face Differential Pot. to Cold Face
Mode Switch
Position
Low
Medium
High
RH Control
Pin No. 32
1 - 2V(1.67V)
2 - 3V(2.17)
2 - 3V(2.3V)
LH Control
Pin No. 31
1 -2V(1.77V)
2 - 3V (2.27V)
1 - 2V (1.19V)
LH Control
Pin No. 31
1 - 2V (1.27V)
1 - 2V (1.4V)
2 - 3V (2.2V)
LH Control
Pin No. 31
1 - 2V(1.63V)
2-3V(2.1V)
2 - 3V(2.2V)
RH Feedback
Pin No. 33
4 - 6V (5.8V)
3 - 5V (3.7V)
1 - 2V (1.22V)
RH Feedback
Pin No. 33
6.5 - 9V (8.7V)
6.9 - 9V (7.5V)
3-5V(4.1V)
RH Feedback
Pin No. 33
6.5 - 9V(6.25)
3 - 5V(4.25V)
3 - 5V (3.7V)
Open Water Temperature Switch Needs
Set Temperature Demand Switch to Midpoint Pin No. 35 1.43 -145V
RH Servo control Pin 32
LH Servo control Pin 31
Short Water Temperature Switch Leads
Mode Switch: Low
Clutch output
RH Servo control
LH Servo control
Set d iff to hot face
Set temp demand to minimum
Recirc. output
High speed relays
Water valve solenoid
Centre vent solenoid
Defrost output
MODE SWITCH: DEFROST
High speed relays
Lower feedback pot.
Upper feedback pot.
MODE SWITCH: OFF
Recirc. output
Pin 20
Pin 32
Pin 31
Pin 28
Pin 35
Pin 3
Pin 16
Pin 17
Pin 18
Pin 27
Pin 27
Pin 16
Pin 29
Pin 30
Pin 44
Pin 3
LH Feedback
Pin No. 22
4 - 6V (5.63V)
3 - 5V (3.4V)
1 -2V (1.27V)
LH Feedback
Pin No. 22
6.5 - 9V (8.7V)
6.5 - 9V (7.5V)
3 -5V (4.0V)
LH Feedback
Pin No. 22
6.5 - 9V(6. IV)
3 - 5V(4.2V)
3 - 5V(3.SV)
0.5V
0.5V
9.3-12.3V
1 -2V
1 -2V
0 - 200mV
0 - 200mV
9.3-12.3V
0 - 200mV
9.3-12.3V
9.3-12.3V
0 - 500mV
150-350mV
9.3-12.3V
2.709-3.1 OOV
1.714-2.014V
0-IV
9.3-12.3V
May 1996 8-33

Air Conditioning
Refrigeration /s:s^°27
Refrigeration
Safety Precautions
The air conditioning system is designed to use only
Refrigerant E134A (dichlorodifluoromethane). Extreme
care must betaken NOT to use
a
methylchloride refrigerant.
The chemical reaction between methylchloride and the
aluminium parts ofthe compressor results in the formation
ofproductswhich burn spontaneously on exposure toair,
or decompose with violence in the presence of moisture.
The suitable refrigerant is supplied under the following
names.
El 34A KLEA or equivalent
Warning: Take care when handling refrigerant. Serious
damage will occur if it is allowed to come into
contact with the eyes. Always wear with goggles
and gloves when working with refrigerant
First Aid
If refrigerant should come into contact with the
eyes or
skin,
splash the eyes or affected area with
cold water for several minutes. DO NOT RUB. As
soon as possible thereafter, obtain treatment from a
Doctor or an eye specialist.
Good Practice

1.
Protective sealing plugs must be fitted to all
disconnected pipes and units.

2.
Theprotectivesealingpiugsmustremain inposition
on ail replacement components and pipes until
immediately before assembly.
3. Any part arriving for assembly without sealing
plugs in position must be returned to the supplier as
defective.

4.
It is essential that a second backing spanner is
always used when tightening or loosening all joints.
This minimises distortion or strain on components
or connecting hoses.
5. Components must not be lifted by connecting

pipes,
hoses or capillary tubes.
6. Care must be taken not to damage fins on the
condenser or evaporator matrices. Any damage
must be rectified by the use of fin combs.
7. Before assembly oftube and hosejoints, use
a
small
amount of clean new refrigerant oil on the sealing
seat.
8. Refrigerant oil for any purpose must be kept very
clean and capped at all times. This prevents the oil
absorbing moisture.
9. Before assembly the condition of joints and flares
must be examined. Dirt and even minor damage
will cause leaks at the high pressure points
encountered in the system.

10.
Dirty end fitting can only be cleaned using a cloth
wetted with alcohol.

11.
Afterremovingsealingplugsand immediatelybefore
assembly, visually check the bore of pipes and
components. Where any dirt or moisture is

discovered,
the part must be rejected.
12. Ail components must be allowed to reach room
temperature before sealing plugs are removed.
This prevents condensation should the component
be cold initially.

13.
Before finally tightening hose connections ensure
that the hose lies in the correct position, is not
kinked or twisted and will not be trapped by
subsequent operations, e.g., refitting or closing
bonnet.

14.
Check that hoses are correctly fitted in clips or
straps.

15.
The compressor must be stored horizontally with
the sump down. It must not be rotated before fitting
and charging. Do not remove the shipping plate
until immediately before assembly. Always use
new "O" ring seals in those joints that incorporate

them.
"O" ring seals should be coated with
compressor oil before fitting.

16.
Components or hoses removed must be sealed
immediately after removal.
1 7. Afterthe system has been opened the receiver-drier
must be renewed.

18.
Before
testing,
run the engine until normal running
temperature is reached. This ensures that sufficient
vacuum is available for test. For cooling tests the
engine must be running for the compressor clutch
to operate.
8-34 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

^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

Field Coil Renewal
/
Gasket Kit Renewal ffi^e^'^^
8.1.02.1 Field Coil Renewal 8.1.03.1 Renew Gasket
Kit

Procedure

1.
Open
the
bonnet
and fit a
wing cover.

2.
Depressurise
the air
conditioning system.
3. Remove
the
compressor.

4.
Remove
the
compressor drive clutch.
5. Remove
the
compressor pulley.
6. Slacken
the
field coil wire clamp screw
(Fig.
1) and

release
the
wire from
the
clamp.

10.

Remove
the
field coil retaining snap ring
and

detach
the
field
coil.

Clean
the
mating face
of the
compressor with
a

cloth moistened with
an
approved cleaning
fluid.

Position
the new
field coil
on the
compressor
and

fit
the
retaining snap
ring.

Route
the
wire
to the
compressor
and fit the
wire
clamp, tighten
the
securing screw.

11.
Fit the
compressor pulley.

12.
Fit the
compressor drive clutch.

13.
Fit the
compressor.

14.
Recharge
the air
conditioning system.

15.
Remove
the
wing cover
and
close
the
bonnet.
Data
Torque Figures
Cylinder head bolts 29.83
to 33.9 Nm.

Procedure

1.
Open
the
bonnet
and fit a
wing cover.

2.
Depressurise
the air
conditioning system.
3. Remove
the
compressor.

4.
Position
the
compressor
in a
vice, tighten
the
vice
onto
the
compressor body lugs.
5. Remove the outlet port blanking plate securing bolt
and detach
the
plate.
6. Remove
and
discard
the 'O'
ring seals from
the

outlet port.
7. Remove
the
compressor cylinder head securing

bolts,
detach
the
cylinder head.
8. Detach
the
valve plate from
the
compressor.
9. Remove
the
gaskets from
the
compressor.

10.
Remove
all
traces
of
gasket material from
the

mating surfaces
of the
cylinder head, valve plate
and cylinder block.
Figure
1.

11.
Position
new
gaskets (Fig.
1 -1
and 3) on the
valve
plate
(Fig. 1-2) and
then place
it on the
cylinder
block.
8-52 May
1996

Air Conditioning
Portable Diagnostic Unit - Signal Monitoring 3^^?
Air Conditioning Signal Monitoring
The following signals can be monitored using the PDU. The abbreviated name of the signal is shown on the PDU
display.
Display Name Full Signal Name
AMBTEMP Ambient temperature sensor
ARECIP Auto-Recirculation input
ARECOP Auto-Recirculation output
AUX+ Auxiliary battery positive
CLUREL Clutch relay drive output
CVSOL Centre vent solenoid
DEFSOL Defrost solenoid
DIFF Temperature differential
EVSEN Evaporator sensor
FANDEF Fanspeed defrost
FANHIG Fanspeed high
FAN LOW Fanspeed low
FANMED Fanspeed medium
FIVEV Five volt supply voltage
FORSERL Lower servo forward drive
FORSERU Upper servo forward drive
GND10 Ground voltage
GND2 Ground voltage
GND38 Ground voltage
GND45 Ground voltage
GND6 Ground voltage
HSREL High speed relay drive
ICSEN In-Car sensor
LBLOFB Left blower feedback voltage
LBLOWOP Left blower output voltage
LSERFB Lower servo feedback potentiometer
MPROBE Measurement probe
POWIN+ Switched power input
POWOP+ Power output
RBLOFB Right blower feedback voltage
RBLOWOP Right blower output voltage
REF Reference signal
REVSERL Lower servo reverse drive
REVSERU Upper servo reverse drive
TEMPDEM Temperature demand
USERFB Upper servo feedback potentiometer
WATSW Water switch
WATVAL Water valve
8-66 May 1996