Electrically Heated Front Seats W/Rheostat Control

Heated Seat Components:

Heated Seat Diagrams:

Locations of components

17 Extra rheostat for the lighting of switches and controls
On the left-hand side of the fascia

22A Fuse holder
In the electrical distribution box, in the engine compartment, on the left-hand wheel housing

57 3-pole connector
Two under the driver's seat
One under the co-driver's seat

59 2-pole connector
One under the co-driver's seat

60 Single-pole connector
Under the centre console, near the ignition switch

64 Heating pad with thermostat
In the seat cushion and backrest of the driver's and co-driver's seats

88 Switch for extra fog lamps
On the fascia

98 10-pole connector
To the left of the steering column, behind the knee shield below the fascia

117 Earthing point
Between the ignition switch and the handbrake lever

121 Seat switch for the heating pad
Under the co-driver's seat, on the left-hand side

152B 9-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.

252 Driver's seat heating rheostat
On the fascia

254 Temperature transmitter for the driver's seat heating pad
In the driver's seat

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 lighting of switch 252 on cars for the US, CA and JP markets, see also the section entitled "Lighting systems, Lighting for controls - US, CA and 1989 for JP".

Driver's seat
Heating pad 64 is supplied from fuse 12 via the red 29-pole connector 152B, and is switched on and off by temperature transmitter 254.

The temperature transmitter is a Negative Temperature Coefficient (NTC) resistor, whose resistance varies 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 0, the heating is switched off, whereas in position 3, the heating is a maximum. When the heating pad temperature 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 from fuse 12 via the same 29-pole connector as the driver's seat. The heating pad is switched on and off by thermostat 64 and 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
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 temperature 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. 224