ignition CHEVROLET DYNASTY 1993 Service Manual

IGNITION COILS
SPARK PLUGS
TORQUE
Ä IGNITION SYSTEMS 8D - 49

INSTRUMENT PANEL AND GAUGES
CONTENTS
page page
AA BODY .............................. 1
AC AND AY BODIES .................... 23 AG AND AJ BODIES
.................... 42
AP BODY ............................. 58
AA BODY INDEX
page page
Cluster and Gauge Service and Testing ........ 2
Electronic Cluster ........................ 13
Fuel GaugeÐFlexible Fuel .................. 2
Gauges ................................. 7
General Information ........................ 1 Instrument Panel
......................... 21
Interior Lamp Replacement ................. 21
Mechanical/Electronic Cluster Removal ......... 5
Switch and Panel Component Service ......... 15
GENERAL INFORMATION
INSTRUMENT CLUSTERS
There are three instrument cluster assemblies. The
mechanical clusters incorporate magnetic type
gauges. The electronic instrument cluster incorpo-
rates, a digital speedometer/odometer and electronic
analog gauges. The mechanical Lo-Line instrument cluster has
magnetic type gauges for coolant temperature, fuel
level and charging system voltage (Fig. 1).
The mechanical Hi-Line instrument cluster has
magnetic type gauges for oil pressure, coolant tem-
perature, charging system voltage and fuel level. The
premium instrument cluster also has a tachometer
(Fig. 2). If the ignition switch is in the OFF position each
gauge will show a reading, except for the volt gauge. However the readings are only accurate when the ig-
nition switch is in the ON position.
TACHOMETER DRIVE MODULE
The tachometer drive module is an electronic mod-
ule used to drive a magnetic tachometer in a conven-
tional instrument cluster.
ELECTRONIC DIGITAL CLOCK
The electronic digital clock is in the radio. The
clock and radio each use the display panel built into
the radio. A digital readout indicates the time in
hours and minutes whenever the ignition switch is in
the ON or ACC position. When the ignition switch is in the OFF position, or
when the radio frequency is being displayed, time
keeping is accurately maintained.
MESSAGE CENTER
The message center includes the graphic display of
the car with illuminating graphics for: low wind-
Fig. 1 Instrument Cluster
Fig. 2 Instrument Cluster With Tachometer
Ä INSTRUMENT PANEL AND GAUGES 8E - 1

SENDING UNIT TEST
When a problem occurs with a cluster gauge, be-
fore disassembling the cluster to check the gauge,
check for a defective sending unit or wiring. (1) Sending units and wiring can be checked by
grounding the connector leads, at the sending unit,
in the vehicle. (2) With the ignition in the ON position; a
grounded input will cause the oil, fuel or tempera-
ture gauge to read at or above maximum.
LOW OIL PRESSURE/CHECK GAUGES WARNING LAMP TEST
The low oil pressure/check gauges warning lamp
will illuminate when the ignition key is turned to
the ON position without starting the vehicle. In the cluster assembly without tachometer, the
low oil pressure lamp will illuminate if the engine oil
pressure drops below a safe oil pressure level. In the cluster assembly with tachometer, the Check
Gauges warning lamp illuminates when there is a
problem in oil pressure level, high engine tempera-
ture or low voltage. To test the system turn ignition key to the ON po-
sition. If the lamp fails to light, inspect for a broken
or disconnected wire at the oil pressure combination
unit, which is located at the front of the engine (Figs.
5 and 6). If the wire at the connector checks good,
pull connector loose from the switch terminal and
with a jumper wire ground connector to the engine
(Fig. 7). With the ignition key turned to the ON po-
sition check the warning lamp. If lamp still fails to
light, inspect for a burned out lamp or disconnected
socket in the cluster.
COMBINATION OIL UNIT TEST
The combination oil unit has two functions:
(1) The normal closed circuit keeps the oil pressure
warning/check gauges lamp on until there is oil pres-
sure (Fig. 7). (2) The sending unit provides a resistance that
varies with oil pressure. (3) To test the normally closed oil lamp circuit, dis-
connect the locking connector and measure the resis-
tance between the switch terminal and the metal
housing. The ohmmeter should read 0 ohms. Start
the engine. (4) If there is oil pressure, the ohmmeter should
read an open circuit. (5) To test the sending unit, measure the resis-
tance between the sending unit terminal and the
metal housing. The ohmmeter should read open.
Start the engine. (6) The ohmmeter should read between 30 to 55
ohms, depending on engine speed, oil temperature,
and oil viscosity. (7) If the above results are not obtained, replace
the switch.
BRAKE SYSTEM WARNING LAMP TEST
The brake warning lamp illuminates when parking
brake is applied with ignition key turned ON. The
same lamp will also illuminate should one of the two
service brake systems fail when brake pedal is ap-
plied. To test system turn ignition key ON, and ap-
ply parking brake. If lamp fails to light, inspect for a
burned out lamp, disconnected socket, a broken orFig. 5 Combination Oil Unit (2.5L)
Fig. 6 Combination Oil Unit (3.0L)
Fig. 7 Combination Oil Unit Test
Ä INSTRUMENT PANEL AND GAUGES 8E - 3

disconnected wire at switch. The lamp also lights
when the ignition switch is turned to START.To test service brake warning system, raise vehicle
on a hoist and open a wheel cylinder bleeder while a helper depresses brake pedal and observes warning
lamp. If lamp fails to light, inspect for a burned out
lamp, disconnected socket, a broken or disconnected
wire at switch. If lamp is not burned out and wire continuity is
proven, replace brake warning switch in brake line
Tee fitting mounted on frame rail in engine compart-
ment below master cylinder (Fig. 8 and 9).
CAUTION: If wheel cylinder bleeder was opened
check master cylinder fluid level.
SEAT BELT WARNING SYSTEM
For testing of this system refer to Group 8M, Re-
straint Systems.
MALFUNCTION INDICATOR (CHECK ENGINE) SYSTEM
For testing this system refer to the Powertrain Di-
agnostic Test Procedures booklet.
AIR BAG WARNING SYSTEM
For testing this system refer to Group 8M, Re-
straint Systems.
Fig. 8 Brake Warning Lamp Switch
Fig. 9 Brake System Warning Lamp Diagnosis
8E - 4 INSTRUMENT PANEL AND GAUGES Ä

(a) Route transmission range indicator guide as-
sembly under left steering column wing and down
left side of column (Fig. 12). (b) Insert flange of column insert into column,
squeeze legs together with tabs under column
jacket and engage lock bar to secure insert (Fig.
14). (c) Hook cable eyelet to steering column actuator
check pointer, should indicate neutral. Do not kink
or bind transmission range indicator guide tube
and position guide tube in original location. (d) Adjust with tool if necessary to center pointer
on N (Neutral) and check in other gears (Fig. 15).
(4) Install upper and lower steering column cover.
(5) Install the rear window defogger bezel and ra-
dio bezel. (6) Install cluster bezel.
(7) Reconnect battery.
REMOVALÐCLUSTER WITHOUT TRANSMISSION RANGE
INDICATOR FROM STEERING COLUMN (1) Remove cluster bezel (Fig. 10).
(2) Remove four screws attaching cluster to base
panel. (3) Pull cluster rearward carefully, reach behind
and disconnect the two harness connectors. (4) Carefully rotate cluster and remove the two
transmission range indicator screws. (5) Remove cluster assembly.
(6) For installation reverse above procedures. (a) Do not kink guide tube when installing clus-
ter. (b) Replace guide tube behind fuse block.
GAUGES
It is not necessary to remove instrument clus-
ter assembly from vehicle for gauge replace-
ment. When removing gauge assemblies from cluster,
gauge must be pulled straight out, not twisted, or
damage to gauge pin may result.
MULTIPLE GAUGE MALFUNCTION
If the fuel, voltage and tachometer gauges appear
to be malfunctioning, remove the cluster assembly.
Check for good pin contact between the wire harness
and printed circuit board. If there is good contact,
check for ignition voltage at ignition cavity C of the
black connector. If there is ignition voltage, check for
continuity between the wire harness ground cavity H
of the black connector and ground. If there is conti-
nuity, replace printed circuit board. If the temperature, oil pressure and speedometer
gauges appear to be malfunctioning remove the clus-
ter assembly. Check for a good contact between the
wire harness and the printed circuit board. If there is
good contact, check for ignition voltage at cavity J of
the red connector. If there is voltage, check for con- tinuity at cavity H of the black connector. If there is
continuity, replace the printed circuit board.
If the temperature, fuel, voltage and speedometer
gauges appear to be malfunctioning, remove the clus-
ter assembly. Check for good pin contact between the
wire harness and the printed circuit board. If there is
good contact, check ignition voltage at cavity J of the
red connector. If there is voltage, check for continuity
at cavity H of the black connector. If there is conti-
nuity, replace the printed circuit board.
GAUGE INOPERATIVE (FIG. 17 THROUGH 23)
(1) Remove gauge in question.
Fig. 17 Fuel Gauge PinsÐWith Tachometer
Fig. 18 Fuel Gauge PinsÐWithout Tachometer
Ä INSTRUMENT PANEL AND GAUGES 8E - 7

(2) With the ignition key ON, check for ignition
voltage at ignition pin of gauge. Check for ground at
ground pin of gauge. Refer to the individual gauge
circuit test for proper pin. (a) If voltage at pin, replace gauge.
(b) If no voltage or ground at gauge pins, check
for ignition voltage and ground at cluster harness
connectors. (c) If no voltage or ground, repair as necessary.
Refer to 8W, Wiring Diagrams. (d) If there is voltage or ground, check cluster for
distorted terminals. If terminals are OK, replace
printed circuit board.
Fig. 19 Voltmeter PinsÐWith Tachometer
Fig. 20 Voltmeter PinsÐWithout Tachometer
Fig. 21 Temperature Gauge PinsÐWith Tachometer
Fig. 22 Temperature Gauge PinsÐWithout Tachometer
Fig. 23 Oil Pressure Gauge PinsÐWith Tachometer
8E - 8 INSTRUMENT PANEL AND GAUGES Ä

(3) When testing temperature, allow the engine to
run until the vehicle reaches a normal operating
temperature. Turn ignition OFF, and remove gauge
from cluster. (a) Testing oil pressure gauge, engine needs to
be running. (b) Measure and record the resistance between
sending unit pin and ground pin of the gauge in
question. Refer to Gauge Calibration. (c) It is important to have the same engine tem-
perature and engine speed when checking temper-
ature and oil pressure gauges position. The time
between gauge position reading and sending unit
measuring should be kept to a minimum. (d) If resistance and gauge position are not sim-
ilar, replace gauge. (e) If OK, test resistance from the sending unit
to the cluster connector. (f) If resistance reading is different, check
printed circuit board for contact to cluster connec-
tor. (g) If OK and contacts are not distorted, replace
printed circuit board. (h) If everything checks out OK, refer to sending
unit test.
(4) If fuel gauge does not meet specifications, refer
to Group 14, Fuel for the test procedure.
GAUGE CALIBRATION
(1) Remove the gauge.
(2) Check for ignition voltage and ground to the
gauge. (3) With the ignition key in the OFF position, re-
place gauge. Turn the ignition key to the ON posi-
tion. To test oil pressure gauge engine must be
running. When testing oil or temperature gauge the
engine should be at normal operating temperature.
Record the gauge position. (4) Remove gauge and record the resistance be-
tween the sending unit pin and the gauge ground
pin. When checking gauges, it is important to have
the same engine temperature and speed when noting
gauge position. The time between gauge reading and
measuring should be kept to a minimum. (5) The Gauge Resistance Chart (Fig. 24), is gen-
eral guidelines for checking the gauge position
against the sending unit resistance. Because of only a few specific points of gauge posi-
tion versus sending unit resistance, a good estimate
is need when the resistance falls between gradua-
tions. Even when the resistance corresponds to grad-
uations, the gauge has a tolerance of 64 ohms.
Volt gauge: The calibration dot on the volt gauge
corresponds to 13 volts between the gauge ignition
and ground pins. If voltage varies from this, estimate
proper gauge position with input voltage.
TACHOMETER REPLACEMENT
(1) Remove cluster, radio and rear window defog-
ger bezels and mask/lens assembly. (2) Remove screws attaching tachometer to cluster
housing. (3) Pull tachometer rearward to remove.
(4) For installation reverse above procedures.
TACHOMETER CIRCUIT TESTING
(1) Remove cluster, radio and rear window defog-
ger bezels and mask/lens assembly. (2) Check for battery voltage at cavity A of the in-
strument cluster black connector. (3) With the ignition in the ON position, check for
battery voltage at cavity C of the black connector
(Fig. 25).
Fig. 24 Gauge Resistance
Fig. 25 Printed Circuit Board 11-Way Connector
Ä INSTRUMENT PANEL AND GAUGES 8E - 9

SPEEDOMETER CIRCUIT TESTING
(1) Remove speedometer from cluster.
(2) With ignition switch in the ON position, check
for battery voltage across ignition and ground pins
(Fig. 28).
(3) Check continuity from vehicle speed sensor sig-
nal pin to connector at vehicle speed sensor. (4) Test for faulty vehicle speed sensor.
(5) If all of these tests prove good, replace speed-
ometer.
VEHICLE SPEED SENSOR REPLACEMENT
(1) Remove harness connector from sensor and
make sure weather seal is on harness connector (Fig.
29). (2) Remove sensor retaining bolt. (3) Pull sensor and pinion gear assembly out of
transaxle. If necessary, carefully pry loose with a flat
blade screwdriver (Fig. 30). (4) Remove pinion gear from sensor.
(5) For installation reverse above procedures and
seat sensor assembly by hand to insure proper gear
engagement. Tighten retaining bolt to 7 N Im (60 in.
lbs.) torque.
Fig. 27 Speedometer Diagnosis
Fig. 28 Speedometer PinsFig. 29 Vehicle Speed Sensor and Connector
Ä INSTRUMENT PANEL AND GAUGES 8E - 11

(3) Remove lamp sockets as necessary by turning
them counterclockwise (Fig. 34 and 35).
PRINTED CIRCUIT BOARD REPLACEMENT
(1) Remove cluster assembly.
(2) Remove tachometer drive module, low fuel re-
lay and gauge alert module (Fig. 32). (3) Remove all cluster lamps.
(4) Remove mounting screws securing printed cir-
cuit board to cluster housing (Fig. 34). (5) For installation reverse above procedures.
ELECTRONIC CLUSTER
SELF DIAGNOSTIC SYSTEM
The electronic clusters (Fig. 36) have an internal
diagnostics routing to isolate problems within the
cluster or sending units. Using the cluster Self-Diagnostic Test will deter-
mine whether problem is within cluster or outside of
cluster (Fig. 37 and 38). Successful completion of the SELF DIAGNOSTIC
TEST indicates that the problem is in the connectors
or sensors outside of the module. Refer to Fig. 39 for
terminal listing.
CONDITION: CLUSTER DISPLAYS DO NOT ILLUMINATE AFTER VEHICLE IS STARTED
PROCEDURE
(1) Check fuses and verify battery and ignition
voltage at cluster connector. (2) Check ground from cluster connector to instru-
ment panel ground stud. (3) Check lamps, replace if necessary.
Fig. 34 Mechanical Cluster Lamp Location
Fig. 33 Gauge Alert Module
Ä INSTRUMENT PANEL AND GAUGES 8E - 13

CONDITION: SPEEDOMETER AND ODOMETER ARE INOPERATIVE OR OPERATESINTERMITTENTLY
PROCEDURE
Check for defective vehicle speed sensor wiring.
CONDITION: OIL GAUGE, FUEL GAUGE, TEMPERATURE GAUGE, OR VOLTAGE GAUGEINOPERATIVE
PROCEDURE
Check for defective sending unit or wiring: (a) Sending units and wiring can be checked by
grounding the connector leads, at the sending unit,
in the vehicle. (b) With the ignition in the ON position, a
grounded input will cause the oil, fuel, or temper-
ature gauge to read maximum.
CONDITION: CLUSTER DISPLAY DOES NOT DIM WHEN HEADLAMP SWITCH ISACTIVATED AND RHEOSTAT ROTATED
PROCEDURE
(1) Check fuses in headlamp circuit.
(2) Check for loose connections or defective wiring
from headlamp switch to the cluster. (3) Check for defective headlamp switch.
(4) The electronic instrument cluster requires both
a marker feed and illumination feed to operate cor-
rectly.
SWITCH AND PANEL COMPONENT SERVICE
HEADLAMP/FOG LAMP SWITCH REPLACEMENT
(1) Remove cluster bezel (Fig. 40).
(2) Remove three screws securing headlamp switch
mounting plate to base panel (Fig. 41). (3) Pull headlamp/fog lamp switch mounting plate
rearward. Disconnect wiring connectors from head-
lamp switch and fog lamp switch pigtail (Fig. 42). (4) Remove knob and stem by depressing button on
bottom of the switch (Fig. 43). (5) Snap-out escutcheon.
(6) Remove fog lamp switch from escutcheon.
(7) Remove nut that attaches headlamp switch to
mounting plate (Fig. 44). (8) For installation reverse above procedures.
FOG LAMP SWITCH TEST
(1) Remove the fog lamp switch from mounting lo-
cation. (2) Disconnect the wiring harness from the switch
pigtail. (3) Using a Ohmmeter, test for continuity between
the terminals of the switch pigtail (Fig. 45). (4) If not OK, replace switch.
LOWER STEERING COLUMN COVERREPLACEMENT
(1) Disconnect park brake release rod from park
brake. (2) Remove fuse box access door and remove screw
from lower column cover (Fig. 46). (3) Remove screws from lower cover, four across
the top and two on bottom. (4) Remove lower steering column cover.
(5) For installation reverse above procedures.
LEFT LOWER INSTRUMENT PANEL SILENCER REPLACEMENT
(1) Remove screws from front of silencer (Fig. 47).
(2) Remove push nut.
(3) Remove silencer.
(4) For installation reverse above procedures.
RIGHT LOWER INSTRUMENT PANEL SILENCER REPLACEMENT
(1) On floor shift vehicles, remove console assem-
bly and center brace bracket. (2) On column shift vehicles, remove center brace
bracket. (3) Remove screws from front of silencer (Fig. 47).
(4) Remove three push nuts from rear of silencer.
(5) Remove lower right silencer.
(6) For installation reverse above procedures.
GLOVE BOX ASSEMBLY REPLACEMENT
(1) Disconnect battery negative cable and isolate
or remove fuse #2 prior to removing switch or wires
may short to ground. (2) Open glove box door and disconnect check
strap. (3) Remove glove box light and switch by squeez-
ing retaining tabs from behind switch mount and
slide rearward. Disconnect wiring connectors. (4) Remove 11 screws from glove box assembly
(Fig. 48). (5) Remove glove box assembly.
Fig. 36 Electronic Cluster
Ä INSTRUMENT PANEL AND GAUGES 8E - 15