SAAB WIS ONLINE

System overview

System overview

Wiring harnesses

The car's electrical system is divided into the following wiring harnesses:


• front

• power train,

- Trionic

- Motronic

- diesel

• dashboard

• rear

• driver's door

• passenger door

• rear door

• roof

• boot lid

• soft-top cover


and some internal harnesses in components, e.g. electrically operated seat.

The wiring harnesses are in contact with each other through connectors, ensuring that all electrical components get the necessary currents, voltages and signals.

Power distribution panels

All power distribution panels are included in the wiring harnesses. In the engine bay there are


• MAXI fuse board 501

• engine bay fuse board 342a

• engine bay relay board 342b


The engine bay fuse and relay boards 342a and 342b are integrated into the same unit.

The dashboard fuse and relay boards form two separate units:


• fuse board 22a

• relay board 22b LHD

• relay board 22b RHD


In the Convertible model there are another two relay boards, one at each of the rear-seat speakers:


• left-hand side 519LH, see

• right-hand side 519RH, see


All fuses are mounted on fuse boards. Only the passenger-seat relay is located apart from the relay boards.

Power supply

The power supply system of the car is divided into:


• Battery feed

• +30 feed

• +15-feed

• +54-feed

• +X-feed

• +B-feed.


Battery feed

Besides the maxi fuse board 501, battery voltage is also fed directly to the starter motor, generator, both lighting relays and a number of fuses in the main fuse board 342a, see Power supply +30, PAGE 1 .

These leads are unfused and greatest care must be exercised when measuring the voltage in these circuits.

The charging system is described in the service category “Charging system”

+30-Voltage

When the ignition is in LOCK position and the key removed, certain fuses and components are still energized. The current comes first via one of the maxi fuses, however, so that there is a certain protection against short circuiting. Great care is also recommended when taking voltage measurements before the fuses in the dashboard fuse board as well as the ignition switch, light switch, ignition switch relay, main relay for the engine management system and starter relay, see Power supply +30, PAGE 2 .

+15-Voltage

When the ignition key is turned to ON or START, current is fed from pin 15 on the switch to a number of fuses in the dashboard main fuse board, see Power supply +15 .

The voltage remains even when the key is turned to the START position.

+54-Voltage

In the ON position, current is also fed from pin 54 on the switch to a few fuses in the dashboard main fuse board and the relay coil in ignition switch relay 21. The relay then operates, supplying fuses both in the engine bay and the dashboard main fuse boards, see Power supply +54 .

When the ignition key is turned to the position START, the current is interrupted. In this manner a great number of power consuming components are disconnected during the starting phase so that the starter motor and engine management system receive as much current as possible to ensure engine start.

+X-voltage

When the ignition key has been turned to OFF from the LOCK position, current will be fed from the X-pin to the light switch, see Power supply +X .

The voltage is interrupted when the key has been turned to the LOCK position.

+B-voltage

When the ignition key has been turned to OFF from the LOCK position, current will be fed from pin B to supply fuse 11 in the dashboard main fuse board, see Power supply +B .

The voltage is first interrupted when the key is removed from the ignition.