Discovery 2. Manual — part 777

INSTRUMENTS

DESCRIPTION AND OPERATION

88-17

Main beam warning lamp

The main beam warning lamp within the instrument pack utilises a clear 14 volt 2 watt long life bulb and a blue legend.
The bulb illuminates when the headlamps are switched to main beam, providing the driver with a visible warning.

There is no self-test performed at ignition on for this warning lamp.

Operating the main beam switch provides the Intelligent Driver Module (IDM) with battery voltage. This feed activates
the IDM to supply the power for the main beam warning lamp. The earth path is provided through the instrument pack.

INSTRUMENTS

88-18

DESCRIPTION AND OPERATION

Anti-lock Brake System (ABS) warning lamp

The ABS warning lamp within the instrument pack utilises an amber LED with a clear legend. If a fault within the ABS
is detected, the SLABS ECU illuminates the LED, providing the driver with a visible warning.

When the ignition is switched on, the SLABS ECU illuminates the LED to provide a self-check, providing there is no
fault it will remain illuminated for 3 seconds or until the ignition is switched off. If an ABS fault is detected while driving
the warning lamp will illuminate to alert the driver.

The power input for the LED is supplied by the instrument pack via fuse 27. The SLABS ECU provides the earth path
to illuminate the ABS warning lamp.

INSTRUMENTS

DESCRIPTION AND OPERATION

88-19

High engine coolant temperature warning lamp

The high engine coolant temperature warning lamp within the instrument pack utilises a red LED and a clear legend.
The ECM illuminates the LED when it detects the engine coolant has exceeded a temperature of 121

°

C (250

°

F) and

switches it off when the coolant temperature drops below 118

°

C (244

°

F). The ECM also illuminates the high engine

coolant temperature warning lamp when it detects the PWM duty cycle to the temperature gauge is out of range. If it
is greater than 94% duty cycle when the engine is hot, or less than 8% duty cycle when the engine is cold, the engine
coolant temperature gauge pointer will indicate cold, thus alerting the driver with an additional visible warning.

When the ignition is switched on, the ECM illuminates the LED to provide a self-check, providing there is no fault it
will remain illuminated for 3 seconds or until the ignition is switched off.

The response of the engine high temperature warning lamp varies according to engine type and market, there are
three conditions:

l

V8 - Gulf.

l

V8 - all markets except Gulf.

l

Diesel - all markets.

The vehicle configuration determines which condition is set.

The PWM duty cycle thresholds for illuminating and extinguishing the warning lamp are given in the table below.

The power input for the LED is supplied by the instrument pack via fuse 27. The ECM controls the earth path to
illuminate the warning lamp.

Market

Lamp on

Lamp off

V8 - Gulf

79.8

±

2%

77.8

±

2%

V8 - all markets except Gulf

77.8

±

2%

75.7

±

2%

Diesel - all markets

78.8

±

2%

76.8

±

2%

INSTRUMENTS

88-20

DESCRIPTION AND OPERATION

Low fuel warning lamp

The low fuel warning lamp within the instrument pack utilises an amber LED and a clear legend. The ECM illuminates
the LED when the fuel gauge pointer has reached 8 degrees from zero. The LED remains illuminated until fuel is
added to move the fuel gauge pointer past 20 degrees from zero. This provides the driver with a visible warning that
the fuel level in the tank is low.

When the ignition is switched on, the ECM illuminates the LED to provide a self-check, providing there is no fault it
will remain illuminated for 3 seconds or until the ignition is switched off.

The sender unit resistance thresholds for switching the lamp on and off are shown in the table below:

The power input for the LED is supplied by the instrument pack via fuse 27. The ECM provides the earth path to
illuminate the warning lamp.

Lamp on

Lamp off

Resistance, ohms

158

±

8

113

±

6

Fuel gauge pointer angle, degrees

8

20