E I ect r ical
15.2.3 COMPONENT DESCRIPTION
15.2.3.1 Speedometer
The speed indication input signal, sent as a pulse rate, is generated by an open collectortransistor within the ABS con- trol module. The instrument pack converts the frequency of this signal to drive the speedometer and to provide two
road speed outputs:
Speed output
1 (pin 2,48 way connector)
This output is connected to the radio head unit, security control module and the power steering module.
Speed output 2 (pin
3,48 way connector)
This output is connected to the body processor unit, cruise control control module, air conditioning control module
and the engine management system.
15.2.3.2 Tachometer
The tachometer input, all engine variants, is provided by the engine management control module. When the engine
is running the control module generates three high state pulses per engine revolution.
15.2.3.3
This signal comes direct from the variable resistance type oil pressure sensor, mounted on the engine. The sensor
resistance values range from 75Q (8 Bar) to 330Q (0 Bar).
When the gauge reaches
a pre-determined reading the instrument pack illuminates the warning light.
Engine Oil Pressure and Warning lamp
15.2.3.4 Engine Coolant Temperature
This signal comes direct from the coolant temperature sensor (variable resistance type), mounted on the engine. The
sensor resistance values range from 34Q (hot) to 241Q (cold), when disconnected from the vehicle.
Note: The coolant temperature gauge is calibrated to indicate at approximately 'Normal' for a wide range of normal
engine operating temperatures.
15.2.3.5 Fuel Tank level Gauge and Warning lamp
This signal (pin 20,24-way connector) comes direct from the variable resistor type fuel level sensor. The sensor resis- tance values range from 80 ohms (full tank) to 900 ohms (empty tank).
When the gauge reaches a pre
-determined reading, the instrument pack illuminates the warning lamp.
15.2.3.6
Battery voltage is displayed on the gauge by measuring the ignition voltage.
The red charge warning lamp will illuminate if either the voltage is too low (below
10.5V) or too high (above 15.5V). In addition, the generator provides a low signal to the instrument pack (pin 9,48-way connector) when battery charging
is unsatisfactory.
Battery Voltage Gauge and Warning lamp
15.2.3.7 Liquid Crystal Display
A single line, six digit, 7 segment display with six trip function flags used for odometer, trip computer and driver mess- ages.
!Y,Q&: If the instrument pack has not been PECUS programmed, the back illumination of the LCD will not switch on.
Check that a PECUS label is attached to the back of the pack.
Issue 1 August 1994 15.2 - 4 X300 EDM
