High Beam Indicator; Diagnosis And Testing - High Beam Indicator; Description; Operation - Jeep Wrangler 2001 Service Manual

8Js - 24 INSTRUMENT CLUSTER
FUEL GAUGE (Continued)
The PCM continually monitors the fuel tank send-
ing unit, then sends the proper messages to the
instrument cluster. For further diagnosis of the fuel
gauge or the instrument cluster circuitry that con-
trols the gauge, (Refer to 8 - ELECTRICAL/INSTRU-
MENT CLUSTER - DIAGNOSIS AND TESTING).
For proper diagnosis of the fuel tank sending unit,
the PCM, the PCI data bus, or the message inputs to
the instrument cluster that control the fuel gauge, a
DRBIII scan tool is required. Refer to the appropri-
ate diagnostic information.

HIGH BEAM INDICATOR

DESCRIPTION

A high beam indicator is standard equipment on
all instrument clusters. The high beam indicator is
located near the upper edge of the instrument cluster
overlay, between the tachometer and the speedome-
ter. The high beam indicator consists of a stencil-like
cutout of the International Control and Display Sym-
bol icon for "High Beam" in the opaque layer of the
instrument cluster overlay. The dark outer layer of
the overlay prevents the indicator from being clearly
visible when it is not illuminated. A blue lens behind
the cutout in the opaque layer of the overlay causes
the icon to appear in blue through the translucent
outer layer of the overlay when it is illuminated from
behind by a replaceable incandescent bulb and bulb
holder unit located on the instrument cluster elec-
tronic circuit board. The high beam indicator is ser-
viced as a unit with the instrument cluster.

OPERATION

The high beam indicator gives an indication to the
vehicle operator when the headlamp high beams are
illuminated, or when the exterior lamps are inadvert-
ently left On. This indicator is controlled by a hard
wired input from the headlamp beam select switch
circuitry of the left multi-function switch to the clus-
ter, and by the instrument cluster electronic circuit
board based upon cluster programming and hard
wired inputs from the head/park/fog lamp switch cir-
cuitry of the left multi-function switch, the driver
door ajar switch, and the ignition switch. The high
beam indicator bulb is grounded on the instrument
cluster electronic circuit board at all times; therefore,
the bulb will be illuminated anytime the headlamp
high beams are turned on, regardless of the ignition
switch position. The bulb only illuminates when it is
provided battery current by the beam select switch
circuitry of the left multi-function switch, or by the
instrument cluster electronic circuit board. The
instrument cluster will turn on the high beam indi-
cator for the following reasons:
2001 JEEP WRANGLER
• Beam Select Switch Input - Each time the
cluster detects battery current on the beam select
switch sense circuit (beam select switch closed = high
beams selected or optical horn feature activated) the
high beam indicator will be illuminated solid. This
input can occur when the headlamp high beams are
selected or when the optical horn feature is activated.
The indicator remains illuminated until the beam
select switch sense input to the cluster is an open cir-
cuit (beam select switch open = high beams not
selected and optical horn feature not activated), or
until the exterior lighting is turned off, whichever
occurs first.
• Exterior Lamps-On Optical Warning - Each
time the cluster detects battery current on the head-
lamp switch output circuit (park or head lamp switch
closed = exterior lighting is On), ground on the driver
door ajar switch sense circuit (driver door ajar switch
closed = driver door is open), and the fused ignition
switch output (run-start) input is an open circuit
(ignition switch is in a position other than On or
Start), the high beam indicator will be flashed On
and Off repeatedly. The indicator will continue to
flash until the exterior lighting is turned Off, the
driver door is closed, or the ignition switch is turned
to the On or Start positions, whichever occurs first.
• Actuator Test - Each time the cluster is put
through the actuator test, the high beam indicator
will be turned on, then off again during the bulb
check portion of the test to confirm the functionality
of the bulb and the cluster control circuitry.
The headlamp beam select switch and circuitry is
integral to the left multi-function switch on the steer-
ing column, and is connected in series between fused
B(+) and the high beam indicator driver circuit input
to the instrument cluster. The left multi-function
switch inputs to the instrument cluster circuitry can
be diagnosed using conventional diagnostic tools and
methods.(Refer to 8 - ELECTRICAL/LAMPS/LIGHT-
ING
SWITCH - OPERATION). For further diagnosis of
the high beam indicator or the instrument cluster
circuitry that controls the indicator bulb, (Refer to 8 -
ELECTRICAL/INSTRUMENT CLUSTER - DIAGNO-
SIS AND TESTING).
DIAGNOSIS AND TESTING - HIGH BEAM
INDICATOR
The diagnosis found here addresses an inoperative
high beam indicator condition. Before beginning this
test, confirm the functionality of the high beam indi-
cator bulb and the cluster control circuitry by per-
forming the instrument cluster actuator test. (Refer
to 8 - ELECTRICAL/INSTRUMENT CLUSTER -
DIAGNOSIS AND TESTING). If the high beam indi-
cator fails to illuminate during the actuator test,
- EXTERIOR/LEFT
TJ
MULTI-FUNCTION