Instrument Cluster; Description - Jeep Wrangler 2001 Service Manual

8Js - 2

INSTRUMENT CLUSTER

INSTRUMENT CLUSTER (Continued)

DESCRIPTION

Fig. 1 Instrument Cluster
1 - CLUSTER BEZEL
2 - INSTRUMENT CLUSTER
The instrument cluster for this model is an Elec-
troMechanical Instrument Cluster (EMIC) module
that is located in the instrument panel above the
steering column opening, directly in front of the
driver (Fig. 1). The EMIC gauges and indicators are
protected by an integral clear plastic cluster lens,
and are visible through a dedicated opening in the
cluster bezel on the instrument panel. Just behind
the cluster lens is the cluster hood and integral clus-
ter mask, which are constructed of molded black
plastic. The cluster hood serves as a visor and shields
the face of the cluster from ambient light and reflec-
tions to reduce glare, while the cluster mask trims
the outside perimeter of the cluster overlay. Behind
the cluster hood and mask is the cluster overlay and
gauges. The overlay is a laminated plastic unit. The
dark, visible, outer surface of the overlay is marked
with all of the gauge identification and graduations,
but this layer is also translucent. The darkness of
this outer layer prevents the cluster from appearing
cluttered or busy by concealing the cluster indicators
that are not illuminated, while the translucence of
this layer allows those indicators and icons that are
illuminated to be readily visible. The underlying
layer of the overlay is opaque and allows light from
the various indicators and illumination lamps behind
it to be visible through the outer layer of the mask
only through predetermined stencil-like cutouts. On
the lower edge of the cluster lens just right of center,
a small molded rubber odometer/trip odometer switch
knob boot covers the switch knob and seals the hole
in the lens through which the knob protrudes. The
remainder of the EMIC, including the mounts and
the electrical connections, are concealed behind the
2001 JEEP WRANGLER
cluster bezel. The molded plastic EMIC housing has
four integral mounting tabs, two on the lower edge of
the housing and one on each side. The EMIC is
secured to the instrument panel structural support
with four screws. All electrical connections to the
EMIC are made at the back of the cluster housing
through two color-coded connector receptacles that
connect the cluster to the vehicle electrical system
through two take outs and connectors of the instru-
ment panel wire harness.
A single EMIC module is offered on this model;
however, some variations of this module exist due to
optional equipment and regulatory requirements.
This module utilizes integrated circuitry and infor-
mation carried on the Programmable Communica-
tions Interface (PCI) data bus network for control of
all gauges and many of the indicators. (Refer to 8 -
ELECTRICAL/ELECTRONIC
ULES/COMMUNICATION - DESCRIPTION). The
EMIC also uses several hard wired inputs in order to
perform its many functions. In addition to instru-
mentation and indicators, the EMIC has hardware
and/or software to support the following functions:
• Chime Warning Service - The EMIC performs
the functions necessary to provide audible alerts to
the vehicle operator and eliminates the need for a
separate chime module. (Refer to 8 - ELECTRICAL/
CHIME/BUZZER - DESCRIPTION).
• Interior Lighting Control Service - The
EMIC performs the functions necessary to provide
control of the interior lighting. This control includes
providing illuminated entry, fade-to-off (theater) dim-
ming, and battery saver (load shedding) features for
all interior courtesy lighting.
• Rear Window Defogger Control and Timer
Service - The EMIC performs the functions neces-
sary to control and time the output to the rear win-
dow defogger on vehicles so equipped and eliminates
the need for a separate control and timer module for
the rear window defogger system. (Refer to 8 -
ELECTRICAL/WINDOW DEFOGGER - DESCRIP-
TION).
• Vacuum Fluorescent Display (VFD) and
Panel Lamps Dimming Service - The EMIC per-
forms the functions necessary to eliminate the need
for a separate dimming module. The cluster converts
an analog input signal from the headlamp and panel
lamps dimmer switches to the appropriate digital,
pulse-width modulated outputs to control the dim-
ming levels of both the instrument cluster and radio
VFDs as well as the incandescent cluster and panel
illumination lighting. This includes providing fea-
tures such as VFD illumination when a door is ajar,
radio illumination control, a parade mode, and dim-
mable cruise, four-wheel drive, and upshift indica-
tors.
TJ
CONTROL MOD-