HEATED FRONT SCREEN
Description
General
The Heated Front Screen (HFS) comprises two separate elements, one RH and one LH.
When the switch is pressed, both elements operate simultaneously. A tell-tale LED is
located in the switch to inform the driver when the HFS is operational.
Operation
Power Distribution
Feed from the positive battery terminal (C0192) is supplied to fusible link 1 and fusible link
5 of the under seat fuse box (C0632) on an N wire. Fusible link 1 (C0575) is connected to
fuse 36 of the passenger compartment fuse box (C0595) by an NO wire. Fuse 36 (C0595)
provides a constant battery feed to the HFS relay (C0994) on an NO wire.
Fusible link 5 is connected to the ignition switch (C1043 on LHD C0028 on RHD) by an NW
wire. When the ignition switch is turned to the 'ignition' position, current flows across the
switch (C1732 on LHD, C0094 on RHD) to fuse 15 of the passenger compartment fuse box
(C0580) on a W wire. Fuse 15 (C0580) provides an ignition feed to the HFS timer unit
(C1623) on an WG wire.
HFS Timer Unit
The HFS timer unit (C1623) monitors the condition of the HFS switch (C0131) by providing
a feed on a KO wire. When the HFS switch is pressed, an earth path is created on a B wire.
In order for the HFS timer unit to operate the HFS, it must also receive an ignition feed from
fuse 15 of the passenger compartment fuse box, and an engine running signal from the oil
pressure switch (C0187) on a WN wire. When both of these are received, the HFS timer unit
(C1623) energises the HFS relay (C0994) by providing a feed to the relay coil on a PY wire.
The relay coil (C0994) is earthed on a B wire.
The energised HFS relay (C0994) provides a feed to the HFS elements (C0247) and the
HFS switch tell-tale LED (C0131) on PS wires. Both are earthed on B wires.