coolant reservoir ASTON MARTIN DB7 1997 Workshop Manual

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

^2?
Air Conditioning Repair Procedures
Hose - Compressor to Evaporator/Air-Con Unit Renew
8.1.06.1 Hose-Compressor
to
Evaporator
Renewal
Procedure

1.
Open the bonnet and fit a wing cover.

2.
Depressurise the air conditioning systenn.
3. Remove the hose to evaporator valve clamping

plate,
disconnect the hose from the valve, remove
and discard the 'O' ring
seal.

4.
Fit a blanking plug to the evaporator valve. Release
the evaporator hose securing clips.
5. Remove the compressor outlet port retaining bolt.
6. Disconnect the hose from the compressor, discard
the hose complete with 'O' ring seals.
7. Connect the hose to the evaporator valve and
tighten clamp onto the hose.
8. Route the hose to the compressor, fit a new 'O' ring
seal and connect it to the compressor.
9. Position the outlet port retaining plate on the
compressor, fit and tighten the securing bolt.

10.
Refit the hose to the clips.

11.
Charge the air conditioning system.

12.
Remove the wing cover and close the bonnet.
8.2.01.1 Air Conditioning Unit Renewal

1.
Disconnect the battery earth
lead.

2.
Drain the engine coolant into a suitable container.
3. Depressurise the air conditioning system.

4.
Disconnect the high and low pressure hoses and
expansion valve from the air conditioning unit (see
expansion valve renewal).
5. Slacken the coolant hose to the heater matrix pipe
securing clips and disconnect the hoses from the
matrix. (This will require the removal of the air
intake hose for access.)
6. Remove the following items from inside the car:
front seats
underscuttle panels/knee bolsters
glove box assembly
facia trim (walnut trim)
radio and ashtray
centre console switch panel assembly
instrument panel and surround trim
steering wheel and column
facia assembly complete
hoses - distribution box to door vents
facia support frame
Details and drawings of the above operations can
be found in the electrical and trim sections.
Disconnect the vacuum hoses from the blower
motors, water valve and reservoir.
Un-clip the electrical harness from the air
conditioningunit, release theelectrical connections
and reposition the harness to allow removal of the
unit.
Displace and remove the footwell ventilator ducts
and hoses (Fig. 1-1).
May 1996 8-55