1993 CHEVROLET DYNASTY key

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

(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

DOOR LAMPS
Pry along top edge of lens and pivot lens out of
lamp. Replace lamp. To remove lamp remove door
trim panel and disconnect all wiring. Flex the tabs of
the lamp retaining bracket and remove lamp.
DOOR KEY CYLINDER LED LAMP
(1) Remove door trim panel. Refer to Group 23,
Body. (2) Assure window is in full up position.
(3) Disconnect LED lamp wiring pig tail and note
wire routing for installation. Use care when remov-
ing lamp so not to disengage lamp retaining clip
from key cylinder (Fig. 52). (4) For installation reverse above procedures.
TRUNK LAMP
The lamp is easily accessible without removing any
components.
Fig. 51 Instrument Panel
Fig. 52 Door Key Cylinder LED Lamp
8E - 22 INSTRUMENT PANEL AND GAUGES Ä

MESSAGE CENTER
The message center is a car graphic warning lamp
module. This conventional warning system and lo-
cated above the headlamp switch.
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. The procedure for setting the clock varies slightly
with each radio. The correct procedure is described
under the individual radio operating instructions re-
ferred to in the Owner's Manual supplied with the
vehicle.
AIR BAG WARNING SYSTEM
For testing of this system refer to Group 8M, Re-
straint Systems.
MECHANICAL CLUSTER AND GAUGE SERVICE
CAUTION: Disconnect negative battery cable, in en-
gine compartment, before servicing instrument
panel. When power is required for test purposes,
reconnect battery cable for the test only.
Disconnect negative battery cable after test and be-
fore continuing service procedures.
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.
CHECK GAUGES WARNING LAMP TESTS
The check gauges warning lamp is illuminated by
the low oil pressure sending unit switch or the body
controller when there is high temperature or charg-
ing system failure. To test the lamp, turn ignition key to the ON po-
sition without starting the vehicle. The low oil pres-
sure switch is grounded and the light will be on
indefinitely. If the lamp fails to light, pull the cluster and check
the following: (a) Continuity between ground and check gauge
pin J (Fig. 3). (b) Proper contact between the gauge pins and
wiring harness and printed circuit board pins. (c) If there is ground and proper pin contact, re-
place lamp. (d) If there is no continuity, check the low oil
pressure sending unit switch (Fig. 4 and 5).
To test the switch disconnect the switch electrical
connector. Attach positive lead of an ohmmeter to
the switch terminal for the gray (GY) wire and the
negative lead to an engine ground. With the engine
Fig. 3 Mechanical Cluster Connectors
8E - 24 INSTRUMENT PANEL AND GAUGES Ä

off, there should be continuity in the system. Start
the engine. With the engine running, the ohmmeter
should show no continuity. If the above results are
not obtained, replace the switch.
BRAKE SYSTEM WARNING LAMP
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 or
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
light. 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.6 and 7). CAUTION: If wheel cylinder bleeder was opened
check master cylinder fluid level.
SEAT BELT WARNING LAMP
For testing of this system, refer to Group 8M, Re-
straint System.
MALFUNCTION INDICATOR (CHECK ENGINE) LAMP
For testing of this system, refer to the Powertrain
Diagnostic Test Procedure Manual.
MECHANICAL/ELECTRONIC CLUSTER REMOVAL
CLUSTER BEZELS REMOVAL
(1) Move gear selector to the low position.
(2) Remove five screws attaching upper bezel to in-
strument panel (Fig. 8). (3) Lift cluster bezel over steering wheel.
(4) Remove four screws attaching lower bezel to in-
strument panel. (5) Lift lower cluster bezel from instrument panel.
(6) For installation reverse above procedures.
CLUSTER MASK AND LENS REMOVAL
(1) Remove cluster bezel.
(2) Remove trip reset knob by pulling straight
back. (3) Remove five screws attaching mask and lens to
cluster. (4) For installation reverse above procedures.
Fig. 4 Combination Oil Sending Unit
Fig. 5 Combination Oil Sending Unit Test
Fig. 6 Brake Warning Lamp Switch
Ä INSTRUMENT PANEL AND GAUGES 8E - 25

or bind the transmission range indicator guide tube
and position guide tube in original location.(5) Adjust with tool if necessary to center pointer
on N (Neutral) and check in other gears (Fig. 14). (6) Install upper and lower steering column cover.
(7) Install the rear window defogger bezel and ra-
dio bezel. (8) Install cluster bezel.
(9) 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 cluster
from vehicle for gauge replacement. When removing
gauge assemblies from cluster, gauge must be pulled
straight out, not twisted, or damage to gauge pins
may result.
MULTIPLE GAUGE MALFUNCTION
If all the instrument cluster gauges appear to be
malfunctioning, remove the cluster assembly.
² Check for good pin contact
² Check for ignition voltage between the IGN cavity
D and ground.
² If there is ignition voltage
² Check for continuity between the wire harness
ground cavity G and ground.
² If there is continuity, replace the print circuit
board (Fig. 16).
GAUGE INOPERATIVE (FIG. 17 THROUGH 20)
(1) Remove gauge in question.
(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 no voltage or ground at gauge pins. Check
cavity D red cluster connector for ignition voltage
or cavity G for ground. (b) If no voltage or ground, repair as necessary.
Refer to 8W, Wiring Diagrams.
Fig. 15 Cluster With Mask and Lens Removed
Fig. 14 Transmission Range Indicator Step 4
8E - 28 INSTRUMENT PANEL AND GAUGES Ä

(b) Refer to sending unit removal Group 14, Fuel.
(c) Connect sending unit wire and jumper wire
as described in the test procedure.
(5) If fuel gauge now checks within specifications,
original sending unit is electrically okay, check fol-
lowing as a possible cause: (a) Ground wire from sending unit to left side
cowl for continuity. (b) Sending unit deformed. Make sure sending
unit float arm moves freely and pick up tube is not
bent upwards creating an interference with bottom
of tank and inspect float. (c) Sending unit improperly installed. Install
properly. (d) Mounting flange on fuel tank for sending
unit deformed. Feel for interference fit of sending
unit to bottom of tank. It is permissible to bend
pick up tube down a little near mounting flange to
gain interference fit. (e) Fuel tank bottom deformed, causing improper
positioning of sending unit pick up tube. Replace or
repair tank and recheck sending unit.
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 resistance Chart (Fig. 21), is general
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.
VOLTMETER REPLACEMENT
(1) Remove cluster bezels and mask (Fig. 22).
(2) Remove screws attaching gauge assembly to
cluster. (3) Pull rearward to disengage gauge from gauge
pins. (4) For installation reverse above procedures.
OIL PRESSURE GAUGE REPLACEMENT
(1) Remove cluster bezels and mask/lens (Fig. 22).
(2) Remove screws attaching gauge assembly to
cluster.
(3) Pull rearward to disengaged gauge from gauge
pins.
(4) For installation reverse above procedures.
FUEL AND TEMPERATURE GAUGE ASSEMBLY REPLACEMENT
(1) Remove cluster bezel and mask/lens (Fig. 22).
(2) Remove oil pressure gauge.
(3) Remove screws attaching gauge assembly to
cluster.
(4) Pull rearward to disengage gauge from gauge
pins.
(5) For installation reverse above procedures.
SPEEDOMETER SYSTEM
AC body vehicles are equipped with electronically
driven speedometer and odometer assemblies. The unit
has the same appearance as a conventional speedometer
but it eliminates the cable-driven mechanical system. A
signal is sent from a transmission-mounted vehicle
speed sensor to the speedometer circuitry through the
wiring harness. By eliminating the speedometer cable,
instrument cluster service and removal is improved. Re-
fer to Fig. 23 Speedometer Diagnosis Chart. When the speedometer is out of calibration. The elec-
tronic automatic transaxle vehicle speed sensor output
must be calibrated to reflect the different combinations
of equipment. The procedure is called Pinion Factor, re-
fer to Group 21, Transaxle for the procedure.
Fig. 21 Gauge Resistance
8E - 30 INSTRUMENT PANEL AND GAUGES Ä