Rolls-Royce Silver Cloud II - Section C.3 ELECTRICAL COMPONENTS

---------- - - Rolls-Royce & Bentley-- - - -- -
Air Conditioning
System Manual
SECTION C.3
ELECTRICAL COMPONENTS
UPPER AIRSTREAM SWITCH
This switch controls the heater and evaporator
flap actuators, the fresh air blower motor, the
compressor clutch
and the water tap actuator.
The switch utilises eight angular positions - the
vertical
or OFF position, four positions clockwise
and three positions anti-clockwise.
In all seven operating positions, with the switch
knob 'in', the fresh air blower motor operates at
medium speed.
When the switch knob is pulled outwards, all
seven conditions
are duplicated but with the
blower motor operating .at full speed. This is
achieved by the provision of a contact sleeve at
the end of the switch spindle. This sleeve connects
two fixed
contacts when the knob is pulled out-
wards, thereby completing a new circuit by-
passing the resistance.
The main switch mechanism consists basically
of five sets of moving contacts which rotate when
the control
knob is turned. Lobes on these con-
tact plates
'make' and 'break' with eleven sets of
fixed contacts spaced around the arc of travel of
the contact Jobes.
A numbered disc is attached to the rear of the
switch for terminal identification, the
key to which
is as
follows:-
Terminal Number
1 Water
Tap 'Leak'.
2 Evaporator Flap Closed.
3 Supply.
5 Heater Flap t Open.
6 Heater Flap Fully Open.
7 Water
Tap Closed.
8 Heater Flap Closed.
9 Compressor Clutch 'In'.
10 Evaporator Flap Fully Open.
11 Blower Motor Medium Speed.
12 Blower Motor Full Speed.
13 Evaporator Flap t Open.
14 Evaporator Flap t Open.
Switch positions
1st clockwise
Evaporator Flap
Heater Flap
Water Tap
Blower Motor
FULLY OPEN
CLOSED
LEAK POSITION
MEDIUM SPEED
Providing Normal ambient air flow at
Medium Speed.
(Heater Matrix warming in
readiness for 2nd position.)
2nd clockwise
Evaporator Flap
Heater Flap
Water Tap ..
Blower Motor
! OPEN
f OPEN
LEAK POSITION
MEDIUM SPEED
Providing Mixed flow of ambient and warm
air.
3rd clockwise
Evaporator Flap
Heater Flap
Water Tap ..
Blower Motor
J OPEN
f OPEN
LEAK POSITION
MEDIUM SPEED
Providing As above, but air of increased
temperature entering the car.
4th clockwise
Evaporator Flap
Heater Flap
Water Tap ..
Blower Motor
CLOSED
FULLY OPEN
LEAK POSITION
MEDIUM SPEED
Providing Maximum air temperature
permitted by coolant leak.
N.B. Knob pulled fully out in any position-
blower motor operates at FULL SPEED.
Page 7