Page 171
2
aut
Electrically heated front seats
Operation
Both front seats of the car are electrically heated.
The heating pads are supplied from fuse 12, via
29-pole white connector 152A. The heating pads are
switched on and off by thermostats 64. These close
the circuit at 14 °C and open it at 28 °C.
The heating pad of the co-driver’s seat is earthed via
seat switch 121. When a load is applied to the seat,
the seat switch will close and the heating pad can be
switched on and off by thermostat 64. This heating
pad will thus be operative only when a person is
seated in the co-driver’s seat.
Fault-tracing hints
The heating pads will be operative when the ignition
switch is in the drive position.
1. Check fuse 12 and check that the supply to it is
live.
2. Check thermostats 64 and check that the supply
to them is live.
3. Check seat switch 121, under the co-driver’s
seat.
4. Check that there is no open circuit in the heating
pad wiring.
5. Check the connectors, cable harnesses and
earth connections.
Saab 900
Page 172
232 Electrically heated front seats
Locations of components
22A
59
60
64
98
ITALY
124
152B
Fuse holder
in the electrical distribution box, in the en-
gine compartment, on the left-hand wheel
housing
2-pole connector
one under each front seat
Single-pole connector
under the centre console, near the ignition
switch
Heating pad with thermostat
in the seat cushion and backrest of the driv-
er’s and co-driver’s seats
10-pole connector
to the left of the steering column, behind the
knee shield below the facia
Earthing point
at the handbrake (1987)
between the ignition switch and the hand-
brake (1988)
Seat switch for the heating pad
under the co-driver’ seat, on the left-hand
side
29-pole red connector
in the engine compartment, in the electrical
distribution box on the left-hand wheel
housing. The connector is accessible from
the interior of the car.
Saab 900
Page 173
Electrically heated front seats 233
Components
in the en-
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‘ignition
the driv-
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Saab 900
Page 174
234 Electrically heated front seats with rheostat control for the driver’s seat
Electrically heated front seats with rheostat
control for the driver's seat
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Saab 900
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Page 175
seat
i i |
Electrically heated front seats with rheostat control for the driver’s seat
239
Operation
Both front seats of the car are electrically heated. On
certain models, heating of the driver's seat can be
controlled by means of a rheostat.
For a complete description of the wiring for the light-
ing of switch 252 on cars for the US, CA and JP
markets, see also the section entitled "Lighting for
controls, US, CA, JP”.
Driver’s seat
Heating pad 64 is supplied from fuse 12 and is
switched on and off by temperature transmitter 254.
The temperature transmitter is a Negative Tempera-
ture Coefficient (NTC) resistor, whose resistance va-
ries with the heating pad temperature.
The temperature of the driver’s seat heating pad can
be set by means of rheostat 252 which has four
positions, marked 0, 1, 2 and 3. In position O, the
heating is switched off, whereas in position 3, the
heating is a maximum. When the heating pad tem-
perature has reached the preset value for a given
rheostat setting, the heating pad will be switched off,
but will be switched on again when the temperature
has dropped to the lower limit for that particular
rheostat setting.
Co-driver’s seat
The heating pad of the co-driver’s seat is supplied
via the same 29-pole connector as the driver’s seat.
The heating pad is switched on and off by thermo-
Stats 64 and is earthed via seat switch sedate
When a load is applied to the seai, the seat switch
will close and the heating pad can be switched on
and off by thermostat 64. This heating pad will thus
be operative only when a person is seated in the
co-driver’s seat.
Fault-tracing hints
1. Set the ignition switch to the drive position.
2. Check fuse 12 and check that the supply to
rheostat 252 is live.
3. Check that there is no open circuit in tempera-
ture transmitter 254. (Measure between pins 6
and 9 of the rheostat.)
4. Check seat switch 121 under the co-driver’s
seat.
5. Check that there is no open circuit in the heating
pad wiring.
6. Check the connectors, cable harnesses and
earth connections.
Saab 900
Page 176
236 _ Electrically heated front seats with rheostat control for the driver’s seat
Locations of components
aby
22A
St
59
60
64
98
ibe br
121
152B
252
254
Extra rheostat for the lighting of switches
and controls
Fuse holder
in the electrical distribution box, in the en-
gine compartment, on the left-hand wheel
housing
3-pole connector
two under the driver’s seat
2-pole connector
two under the co-driver’s seat
Single-pole connector
under the centre console, near the ignition
switch
Heating pad with thermostat
in the seat cushion and backrest of the driv-
er’s and co-driver’s seats
10-pole connector
to the left of the steering column, behind the
knee shield below the facia
Earthing point
at the handbrake (1987)
between the ignition switch and the hand-
brake (1988)
Seat switch for the heating pad
under the co-driver’s seat, on the left-hand
side
29-pole red connector
inthe engine compartment, in the electrical
distribution box on the left-hand wheel
housing. The connector is accessible from
the interior of the car.
Driver's seat heating rheostat
on the facia
Temperature transmitter for the driver’s seat
heating pad
in the driver’s seat
Saab 900
)
wd
Page 177
j Electrically heated front seats with rheostat control for the driver’s seat 237
seat
Components
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seat &)
Saab 900
Page 178
y 238 _ Electric heating for the rear window
Electric heating for the rear window
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Saab 900
Page 179
£
Electric heating for the rear window 239
Operation
The electric heating of the rear window can be
switched on and off by means of switch 116. The
switch is spring-loaded and is combined with a
time-delay relay. For a complete description of the
wiring for the lighting of the switch on cars for the US,
CA and JP markets, see also the section entitled
"Lighting for controls, US, CA, JP".
The switch is supplied from fuse 13, via the 29-pole
red connector 152B (when the ignition switch is in
the drive position).
When the switch is depressed, relay 113 will be
energised. Warning lamp 47J in the combined in-
strument will light up.
Electric heater 115 for the rear window is supplied
from fuse 29, via the relay contacts.
On the 3-D and 5-D models, the electric heating of
the rear window is earthed to the tailgate, which, in
turn, is earthed to earthing point 9 (cable 211A
black).
Time-delay relay
On the following markets, relay 113 is replaced by a
time-delay relay and spring-loaded switch 116.
U.S.A., Canada, Japan, Middle East, Far East and
Australia. ~
After the switch has been depressed and the relay
has been energised, the time circuit in the relay will
be supplied (terminal 15) from fuse 22. After around
10 minutes, the relay will switch off the supply to the
electric heating for the rear window. If the switch is
depressed when the heating is on, the relay will trip.
When the electric heating for the rear window is
switched on, warning lamp 47J will be supplied from
terminal E of the relay.
If the ignition is switched off while the electric heat-
ing for the rear window is switched on, the supply to
terminal 15 will be opened, and the relay will immedi-
ately switch off the supply to the heating element for
the rear window.
US and CA markets (1988 model)
The time-delay relay also controls the heating of the
rear-view mirrors.
Fault-tracing hints
The electric heating for the rear window will be oper-
ative when the ignition switch is in the drive position.
1. Check fuses 13 and 29 and check that the sup-
ply to them is live. (On certain markets, also
fuse 22.)
2. Check that the supply to the switch and terminal
30 of the relay is live.
3. Check the relay: Press the switch and check that
the supply to the electric heating for the rear
window is live.
4. Check the connectors, cable harnesses and
earth connections.
Saab 900
Page 180
240
Electric heating for the rear window
Locations of components
3 Earthing point in the facia
17 Extra rheostat for the lighting of switches
and controls
22A Fuse holder
in the electrical distribution box, in the en-
gine compartment, on the left-hand wheel
housing
47) Rear window heater warning lamp
in the combined instrument on the instru-
ment panel
48 Cigarette lighter
on the facia
57 3-pole connector
in the luggage compartment, at the left-
hand air outlet
59 2-pole connector
in the luggage compartment, at the left-
hand air outlet
113 Relay for the electrically heated rear window
in the electrical distribution box in the en-
gine compartment, on the left-hand wheel
housing
115 Electric heater for the rear window
116 Switch for the electrically heated rear win-
dow
in the centre of the facia
152A 29-pole white connector
152B 29-pole red connector
in the electrical distribution box in the en-
gine compartment, on the left-hand wheel
housing.
The connectors are accessible from the inte-
rior of the car
158 Negative distribution terminal
159 Distribution terminal +15
in the electrical distribution box, in the en-
gine compartment, on the left-hand wheel
housing
207 Electrically-heated rear-view mirrors
one on each front door