
Group 38 Instrumentation, VNL, VNM Design and Function
Graphic Display
The Graphic Display is located below the gauges in the
left section of the instrument cluster. It displays vehicle
system information not available from the other gauges,
and helps the driver obtain maximum efficiency from the
vehicle.
Standard displays include clock, alarm clock, voltmeter,
engine hours, two resettable trip odometers, a fuel econ-
omy display and diagnostic information. Optional displays
include engine and transmission oil temperature gauges.
Displayed data can come from:
•the J1587 data link
•external switches
•external sensors.
The display can be customized to suit individual prefer-
ences. For example, its backlighting can be adjusted
independently of gauge backlighting.
When the ignition is on and the vehicle is not moving,
the Graphic Display can also be used to help diagnose
the cluster and external problems.
If battery power is lost, the Graphic Display will default to
the clock display. When power is regained, the clock will
come on, flashing, and will need to be reset.
Automatically Activated Warnings
T3009004
Fig. 14:
Automatically Activated Telltale Warnings Appear-
ing in the Graphic Display
Should a condition requiring attention occur, a telltale
warning message identifying that condition will override
the current display. For example, if the engine coolant
level drops below a predetermined point while the clock
is displayed, a low coolant display will replace the clock
display.
Telltale Warnings:
Low coolant
•The low coolant warning display is activated by an
input from the low coolant sensor, and will stay on
until the problem is corrected.
•Note that engine shutdown mode may be engaged
by a low coolant condition (this is an engine depen-
dent parameter).
•The low coolant sensor is a normally open switch,
and is closed by a low coolant level. To clear the low
coolant display, check for proper coolant level. If
adding coolant does not correct the problem, check
the coolant sensor for continuity between pins A and
B. If continuity exists replace the faulty sensor. If
there is no continuity check the wiring for a short to
ground.
Air filter restriction
•The air filter restriction display and a buzzer will
sound ONLY during the first 10 seconds after igni-
tion. The air filter restriction sensor is a normally
open switch closed by approx. 25 Hg.
•If this warning appears, check the air filter restriction
gauge at the air filter assembly to see that it has an
approximate reading of 25 Hg. If so, replace the fil-
ter and reset the mechanical gauge at the air filter. If
the gauge is not reset, the warning will still appear
in the instrument cluster.
•If the warning still appears after these steps, check
the air filter restriction gauge for continuity between
pins A and C. If there is continuity between pins A
and C replace the air filter restriction gauge.
•If the warning still appears after these steps, trou-
bleshoot the air filter restriction gauge circuit.
Washer fluid low
•The washer fluid low warning will be displayed when
the washer fluid drops below a predetermined level.
The washer fluid low warning is a normally open
switch located on the washer fluid pump assembly,
which is closed by a low washer fluid condition.
•The warning activation has a 12 second delay to al-
low for fluid slosh.
•This warning may be cleared by pressing the Set
button on the wiper/washer stalk. The warning will
reappear each time the key is cycled off and on.
•If adding washer fluid does not clear the warning,
check the washer fluid pump assembly for continuity
between connector pins B and C. If there is continu-
ity, replace the pump assembly. If the warning is still
displayed, troubleshoot the washer fluid pump cir-
cuit.
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