9000 L4-1985cc 2.0L DOHC Turbo EFI (1987)
228B Filament monitor
In the electrical distribution box in the engine compartment, behind the left-hand headlamp (1988)
Operation
Parts of the external lighting system of the car are supervised by filament monitor 228A and pictogram 213. The filament monitor is produced in a
number of versions, to suit the various markets.
The pictogram also includes four lamps which will light up if the corresponding doors are not properly closed. The latter function is discussed
separately in the section entitled "Pictogram - Door indication".
Filament monitor
The common feature of all market variants is that the filament monitor contains three monitoring relays for the following lights:
Dipped beam filament 12
Brake lamps 30
Rear lights 14
These relays actuate the lamps in pictogram 213. The lamp to the left indicates faults on the front lights of the car, whereas the lamp to the right
indicates faults on the rear lights of the car. Warning lamp 47D for the oil pressure is discussed below.
The lamp in the centre (central warning) lights up the contour of the car in the pictogram and will always light up whenever a fault is indicated.
The coil of every relay has two windings through which the corresponding lighting circuit is supplied.
When ignition switch 20 is in the drive position, a positive voltage will be supplied across fuse 13 and terminal +15 (159) to terminal 7 of the
pictogram.
If an open-circuit should occur in one of the two lighting circuits, e.g. for dipped beam filaments 12, the resulting unbalance will cause the relay to be
energized. The relay contacts will then close and terminal C2 will be earthed. The circuit for the left-hand lamp and the central warning lamp of the
pictogram will be earthed and the lamps will light up.
If an open-circuit should occur in the supply to both lamps in an external lighting circuit, no unbalance will occur and no fault indication will therefore
be provided.
If fuse 29 or 30 for the parking lights should blow, unbalance will occur in the filament monitor relay for the rear lights and fault indication will then
be provided on the pictogram. This is due to the fact that the filament monitor relay for the rear lights has a separate supply from fuse 29 or 30.
Oil pressure warning lamp
The oil pressure warning lamp is intended to warn the driver that the engine oil pressure is below the predetermined value.
When the ignition switch is in the drive position, a positive voltage will be supplied to oil pressure transmitter 44, across fuse 13 and terminal +15 in
the electrical distribution box, and across warning lamp 47D located in pictogram 213. If the lubricating oil pressure should drop below 0.3-0.5 bar,
the oil pressure transmitter will close the circuit and the lamp will light up.
At the same time as lamp 47D is earthed and lights up, the central warning lamp of the pictogram will be earthed, causing the pictogram to light up.
Cars for the European market (except SE, FI and GB)
Cars for the European market differ in that the filament monitor includes an additional circuit for supervising brake light switch 29. The supply for the
circuit is taken from terminal +15.
The system is performing correctly if the pictogram warning lamp for the rear lights lights up when the ignition is switched on, and is then switched off
when the brake pedal has been depressed.
Cars for the US and CA markets
Cars for these markets differ in that a special supervisory function is added for high-level brake light 109. If the car is braked (pin 54 live) and the
bulb in the high-level brake light does not light up, terminal C1 will be earthed. The pictogram will then indicate a fault in the rear lights.
Testing of Indicating and warning lamps
Certain bulbs in pictogram 213 can be checked by setting ignition switch 20 to a special test position. The test position is between the drive and start
positions of the ignition switch.
When the ignition switch is set to the drive position, the lamps to be tested will receive a positive supply across fuse 13 and terminal +15. (Terminal 7
on the pictogram).
