key battery ASTON MARTIN DB7 1997 Workshop Manual

Electrics
Electric Windows - Fault Analysis / Window Motor Removal
[n:m3^^

Electric Windows
Description
Power to the window wind circuits is available
when the ignition switch is on and is supplied
through a thermal cut-out to the left and right
window switches. The switches are double pole
plus earth so that the current through a window
motor may be switched in either direction to raise
or lower the window.
DB7 uses frameless door windows which seal
against rubber strips around the body shell door

opening.
To avoid damaging these seals during
door opening, the door glass must be lowered
before the door can be opened. This function is
controlled by the window control units. The units
are mounted on the inside of each door frame and
will sense if a door handle is pulled to open the
door. Before releasing the door lock, the control
unit will drive the window wind motor briefly to
lower the door window glass down until it clears
the window seals. Similarly, after closing a door,
the window motor will be run to raise the door glass
to seat the glass against the body seals.
Fault Analysis Procedure
a) If a window fails to operate, check for fuse failure
and the connectors for poor or open contacts.
b) Check the thermal cut-out by shorting across it and
operating either window. If the windows operate
with the short
ci rcu
it but not without, the cut-out is
faulty.
c) With the ignition on, battery voltage should be
available between the inputterminalsof the switches
and chassis. Operate each switch and ensure that
battery voltage is available between the switch
output terminals and chassis.
d) Measure voltagefrom each switch inputterminalto
the switch earth return terminal. If no voltage is

measured,
the earth return line is open circuit.
e) Measure continuity through the wiring from the
switches to each motor. If continuity is correct,
remove the motor for bench testing.
6.7.04 Door Window Motor
Procedure

1.
Remove the door trim panel and the glass inner
sealing
trim.

Figure!. Window Securing Screws
2. Position the window to gain access to the slider
bracket and glass securing screws.
3. Disconnect the battery earth
lead.

4.
Remove two screws securing the glass to each of
the two slider brackets. Loosen the two screws
securing the glass to the elevator
rail.

6. Slide the elevator rail forwards until the glass
securing screws are opposite the wide opening of
the rail keyhole slots and remove the glass from the
top of the door.
7. Disconnect the window motor multiplug.
6-14 May 1996

^=2?
Electrics
Airbag System
Eye Protection
Chemical protective goggles are recommended
where there is a possibility of eye contact with the
propellant. Safety glasses with side shields are
recommended for all other operations.
Protective Clothing
Approved protective gloves, overalls and shoes/
boots should be worn.
Handling and Storage Precautions
Do not store airbag modules near live electrical
equipment or circuitry. Store in a dry environment
at ambient temperatures.
Good housekeeping and engineering practices
should be employed to prevent the generation and
accumulation of
dusts.
Store in compliance with all
local state and federal regulations.
Driver and Passenger Airbag Modules
Assembly/Removal/Service Instructions
WARNING: In the event of a vehicle impact where the
airbags and the seatbeltpretensioner (if fitted) are
deployed, the following actions MUST be
performed:
Check the condition of the seatbelts, steering

wheel,
steering column, all connections to airbags,
and the column switchgear connectors for integrity
and damage. If in any
doubt,
replace suspected
parts for new parts.
Replace both crash
sensors,
the
safing sensor
and
the seatbelt pretensioner module (if fitted).
On completion of all repair procedures, switch on
the ignition and check that the
Airbag/SRS
warning
light comes on when the ignition is switched on
and extinguishes after approximately six seconds
indicating satisfactory completion of the airbag
and pretensioner
system
self
tests.

WARNING: Before starting
work,
ensure
that the ignition
switch is in position 'O' and the ignition key is

removed.
Disconnect the battery negative lead
within 12 seconds of switching off the ignition to
prevent the alarm system triggering.
As the airbag control module is equipped with a
back-up power source and due to the risk of the
airbag being inadvertently deployed, wait one
minute or longer after disconnecting the battery
before starting work on the airbag module.
• Disconnectingthe battery negative cable cancels
the memory for the 'one-touch' window down
system and stops the vehicle clock. Reset the
window memory and the clock when work is

completed.

• Never use airbags from other vehicles, always
use new parts.
• After work is completed, reconnect the battery
and perform the airbag warning light check
• Never use electrical probes to check voltage or
electrical resistance of the airbag modules.
• Disconnect the airbag before carrying out any
work on, or in the vicinity of the module, or
when using electric welding equipment.
• Always ensure that the battery negative lead has
been disconnected for at least one minute before
commencing any removal procedure.
September 1996 6-71

'=2?
Electrics
Airbag System
4.5.01.3 Driver's Airbag Module Renew
Read and adhere to all warnings and safety
procedures quoted at the start of this section when
working on airbag modules.

1.
Ensure that the steering system is centralised and
that the steering wheel is in the lowest tilt position.

2.
Disconnect the vehicle battery and insulate the
battery lead to avoid accidental reconnection. Wait
for at least one minute before proceeding with work
on the removal of the airbag.
Hote: The vehicle battery
must be
disconnected within
12 seconds of switching off
the
ignition to avoid the alarm
siren sounding.
5. Carefully remove the module from the steering
wheel and disconnect the airbag module multi-

plug.

6. To ensure personal safety, double check that the
battery is still disconnected and the battery lead
safely insulated. Connect the new airbag module

multi-plug.
Fit and align the new module to the
steering wheel and tighten the two securing torx
screws. Return the steering to the straight ahead

position.

7. Remove the battery lead insulation and reconnect
the battery
lead.

Note:
The vehicle
clockandthe window control unitwill
need
resetting
after completion of
this
procedure.
8. Switch on the ignition and check that the airbag
warni ng
I
ight comes on when the ignition is switched
on and extinguishes after approximately sixseconds
indicating satisfactory completion of the airbag
system self tests.
Insert the ignition key and turn to position I. Turn
the steering wheel to the left, 90° from its straight
ahead position, and loosen thefirstmoduiesecuring
torx screw.
Turn the steering wheehSO" to the rightand loosen
the second module securing torx screw.
September 1996 6-75

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

'^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

'=^
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