08/06
Section 6
Electrical
6-3
Central Instrument Cluster
The central instrument cluster includes the speedometer (including odometer and trip meter) and tachometer (including
engine hour meter and outside temperature display), plus pre-installed standard and/or editable warning light symbols
called “telltale” cards.
Each “telltale” card slides into the left and right sides of the cluster. The standard cards cover most warning light
requirements; editable cards can be used for less common components that also require warning lights.
The central instrument cluster receives input data from the CECU via the “I-CAN” (see Figure 6-6) data bus. When the ig-
nition key is rst turned ON, the cluster will perform a calibration “power on self-test”. Please see pages 6-18 through 6-20
for more detailed information on customizing telltails.
Power On Self-Test
• Ignition key turned ON.
• The speedometer and tachometer gauge pointers move from pointing at zero, counter-clockwise to their me-
chanical limit (approx. -8°), stay there for one second and go back to pointing at zero.
• At the same time, all LED indicators and telltales are switched on together, and then switched off together.
• A “Warning” sound sequence is also activated ve times without break.
The warning lamps in the cluster are all activated by the CECU, except for Telltale Position 5 (usually Refrigerator) and
Position 11 (editable) which are wired directly to the cluster. The CECU receives direct wire inputs for all warning lamps
with the exception of the Low Coolant Level warning and the Traction Control/Stability Control lamp. These lamp inputs
are received via the J1939 (Vehicle CAN) data link. The CECU typically receives the Trailer ABS warnings via the J1939
(Vehicle CAN) data link, however it can also be direct wired to the CECU from the ABS unit on the trailer, if required.
FIGURE 6-2. Instrument Cluster Componentry.
Baseline Cluster
Telltale cards
pre-installed
in slots on
both sides of
cluster
Card locks into place -
Installation tab breaks off
The cluster is installed with four screws
Single electrical connection on back of cluster
Telltale cards
pre-installed
in slots on
both sides of
cluster.
Baseline Cluster
Card locks into place –
installation tab breaks off
Telltale cards
The cluster is installed with four screws
Single electrical connection on back of cluster
Standard card
Editable card
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