Dodge RAM TRUCK 1500 1995 Service Manual page 416

IE - i INSTRUMENT PANEL AND GAUGES
MMIT-TO-START LAMP
This lamp is used on diesel engine models only.
The wait-to-start lamp in the message center is
turned on by the PCM after the ignition switch is
turned to the ON position. It gives the driver an in­
dication to wait until the intake manifold air heater
grid has had sufficient time to heat up the intake air
for a good quality start. The intake manifold preheat
cycle is controlled by an electronic air heater control
module. The lamp will turn off if the driver turns the
ignition switch to the START position before the
lamp times out on its own. Refer to Group 14 - Fuel
Systems for more information.
WATER-IN-FUEL LAMP
This lamp is used on diesel engine models only.
The water-in-fuel lamp in the message center is
turned on by the PCM to warn the driver when the
water-in-fuel sensor signal indicates that excess wa­
ter has accumulated in the fuel filter. The lamp
should go off automatically when the excess water
has been drained. Refer to Group 14 - Fuel Systems
for more information.
CLUSTER ILLUMINATION LAMPS
All cluster illumination lamps receive battery feed
from the instrument lamps fuse in the fuseblock
module through the panel dimmer rheostat of the
headlamp switch. When the park or headlamps are
on, the cluster illumination lamps light. Illumination
brightness can be adjusted by rotating the headlamp
switch knob (clockwise to dim, counterclockwise to
brighten).
O I A O H O S I S
GAUGES
If an individual gauge is inoperative, see the diag­
nostic procedure under the heading for that gauge. If
more than one gauge is inoperative, perform the fol­
lowing:
(1) Check fuse 12 in the fuseblock module. If OK,
go to next step. If not OK, replace fuse.
(2) Check for battery voltage at fuse 12 with igni­
tion switch in ON position. If OK, go to next step. If
not OK, repair open in circuit from ignition switch
and/or refer to Group 8D - Ignition Systems for test­
ing of ignition switch.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Unplug gauge cluster connector B
(black connector).
(4) Connect battery negative cable. Turn ignition
switch to ON. Check for battery voltage at cavity 8 of
cluster connector B. If OK, go to next step. If not OK,
repair open in circuit from fuse 12 as required.
(5) Turn ignition switch to OFF. Disconnect battery
negative cable. Unplug gauge cluster connector A
(white connector). Probe cavities 6 and 10 of cluster
connector A. Also probe cavity 9 of cluster connector
B. Check for continuity to a good ground. There
should be continuity. If OK, replace gauge cluster
printed circuit. If not OK, repair open in circuit(s) to
ground as required.
COOLANT TEMPERATURE GAUGE
The diagnosis found here addresses an inoperative
gauge condition. If the problem being diagnosed is re­
lated to gauge accuracy, be certain to confirm that
problem is with gauge and not with cooling system
performance. Actual engine coolant temperature
should be checked with a test gauge or thermometer
and compared to gauge readings before you proceed
with gauge diagnosis. Refer to Group 7 - Cooling Sys­
tem for more information.
(1) Turn ignition switch to ON. Disconnect coolant
temperature sending unit connector (Figs. 4, 5 or 6).
The gauge needle should move to low end of gauge
scale. If OK, go to next step. If not OK, go to step 3.
(2) Install a jumper wire from sending unit wiring
Fig. 4 Coolant Temperature Sending Unit - V-6/V-8
Engine
to ground. The gauge needle should move to high end
of gauge scale. If OK, replace sending unit. If not
OK, remove jumper wire and go to next step.
(3) Turn ignition switch to OFF. Disconnect battery
negative cable. Remove instrument cluster bezel and
cluster assembly. Disconnect cluster connector A
(white connector).