CHEVROLET DYNASTY 1993 Service Manual

(c) If there is voltage or ground, check cluster for
distorted terminals. If terminals are OK, replace
printed circuit board.
(3) When testing temperature and oil pressure
gauges allow the engine to run until the vehicle
reaches a normal operating temperature. Turn igni-
tion 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) When checking temperature and oil pressure
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. (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. (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 meets specifications check fuel
tank and original fuel tank sending unit as follow: (a) Carefully remove fuel tank sending unit from
tank.
Fig. 16 Printed Circuit Board
Fig. 17 Fuel Gauge Pins
Fig. 18 Voltmeter Pins
Fig. 19 Temperature Gauge Pins
Fig. 20 Oil Pressure Gauge Pins
Ä INSTRUMENT PANEL AND GAUGES 8E - 29

(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

SPEEDOMETER ODOMETER ASSEMBLY REPLACEMENT
(1) Remove cluster bezel and mask/lens.
(2) Remove volt gauge.
(3) Remove screws attaching gauge assembly to
cluster. (4) Pull speedometer rearward to disengage from
gauge pins.
(5) For installation: Position speedometer on gauge
pins and push firmly until seated and reverse above
procedures.
SPEEDOMETER CIRCUIT TESTING
(1) Using the DRB II, check vehicle speed sensor
for fault code and for proper speed indication. Refer
to Powertrain Diagnostics Procedure Manual, Speed
Control System Test. (2) Remove speedometer from cluster.
(3) With ignition on check for battery voltage
across ignition and ground pins (Fig. 24). (4) Check for continuity from vehicle speed sensor
signal pin to connector at speed sensor.
VEHICLE SPEED SENSOR REPLACEMENT
(1) Remove harness connector from sensor and
make sure the weather seal is on harness connector
(Figs. 25 and 26). (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. (4) Remove pinion gear from sensor.
Fig. 22 Cluster with Mask and Lens Removed
Fig. 23 Speedometer Diagnosis
Ä INSTRUMENT PANEL AND GAUGES 8E - 31

(5) For installation reverse above procedures. Seat
sensor assembly by hand to insure proper gear en-
gagement. Tighten retaining bolt to 7 N Im (60 in.
lbs.) torque.
ELECTRONIC AUTOMATIC TRANSAXLE VEHICLE SPEED SENSOR REPLACEMENT
The output vehicle speed sensor is located to the
left of the manual shift lever. (1) Raise and support vehicle on safety stands.
(2) Remove vehicle speed sensor (Fig. 27).
(3) For installation, reverse above procedures.
VEHICLE SPEED SENSOR TEST
For testing of the vehicle speed and related compo-
nents, refer to the Powertrain Diagnostics Test Pro-
cedure Manual.
PRINTED CIRCUIT BOARD REPLACEMENT
(1) Remove cluster assembly, refer to Cluster As-
sembly Replacement. (2) Twist out all lamp sockets.
(3) Remove screws securing printed circuit board
to cluster housing (Fig. 11). (4) Pull printed circuit board straight out and
avoid bending the board. (5) For installation reverse above procedures. Be
sure that all gauge pins are carefully aligned.
CLUSTER LAMPS REPLACEMENT
All cluster lamps are one-piece lamp and socket as-
semblies. Can be replaced by removing cluster as-
sembly from instrument panel. Replace appropriate
lamp shown in rear view of cluster (Fig. 28).
Fig. 24 Speedometer Pins
Fig. 25 Vehicle Speed Sensor and Connector
Fig. 26 Vehicle Speed Sensor and Speedometer Pinion
Fig. 27 Vehicle Speed Sensor Removal
8E - 32 INSTRUMENT PANEL AND GAUGES Ä

Fig. 28 Instrument Cluster Illumination Lamp
Ä INSTRUMENT PANEL AND GAUGES 8E - 33

ELECTRONIC CLUSTER
SELF DIAGNOSTIC SYSTEM
The electronic clusters have an internal diagnostics
routing to isolate problems within the cluster or CCD
Bus. Using the cluster Self-Diagnostic Test will deter-
mine whether the problem is within the cluster or
outside of cluster (Fig. 29 and 30). Successful completion of the Self Diagnostic Test
indicates that the problem is in the CCD Bus, inter-
facing modules, connectors, or sensors outside of the
cluster. Refer to Fig. 31 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.
CONDITION: CLUSTER ASTERISK (*) FLASHES, CLUSTER DISPLAYS NOTINDICATING CORRECT DATA.
PROCEDURE
CCD bus problem. Use the Body Chassis Diagnos-
tic Manual to diagnose CCD Bus.
CONDITION: SPEEDOMETER AND ODOMETER ARE INOPERATIVE OR OPERATESINTERMITTENTLY
PROCEDURE
(1) If speedometer reads 0, or odometer is blank,
and cluster asterisk is flashing, use the Body Chassis
Diagnostic Manual to diagnose CCD Bus problem. (2) If cluster asterisk is not flashing, check for de-
fective vehicle speed sensor or speed sensor wiring.
CONDITION: OIL GAUGE, FUEL GAUGE, TEMPERATURE GAUGE, OR VOLTAGE GAUGEINOPERATIVE
PROCEDURE
If any gauge gives no indication and cluster aster-
isk is flashing, use the Body Chassis Manual to diag-
nose CCD Bus problem. If cluster asterisk is not flashing:
(1) 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. (2) If the problem is with the oil, temperature, or
fuel gauge, check the body controller. If the problem
is with the voltage gauge, check the powertrain con-
trol module operation.
CONDITION: CLUSTER DISPLAY DOES NOT DIM WHEN HEADLAMP SWITCH ISACTIVATED AND RHEOSTAT ROTATED
PROCEDURE
If the cluster asterisk is flashing, Refer to the Body
Chassis Diagnostic Manual to diagnose the CCD Bus. If the cluster asterisk is not flashing:
(1) Check fuses in headlamp circuit.
(2) Check for loose connections or defective wiring
for headlamp switch to body controller. (3) Check for defective headlamp switch. The elec-
tronic instrument cluster receives the display inten-
sity status from the body controller via the CCD Bus.
CONDITION: SEAT BELT WARNING LAMP DOES NOT ILLUMINATE
PROCEDURE
Turn on ignition. Lamp should illuminate for six
seconds. If not: (1) Check for burned out lamp and retest.
(2) Replace cluster.
CONDITION: LOW WASHER, DOOR/DECK, OR MALFUNCTION INDICATOR (CHECK ENGINE)LAMP, DO NOT ILLUMINATE
PROCEDURE
(1) Perform cluster self-diagnostics to determine if
lamp will illuminate. If lamp does not, check for
burned out lamp, replace and retest. (2) If cluster asterisk is flashing, Refer to the Body
Chassis Diagnostic Manual to diagnose CCD Bus. (3) If cluster asterisk is not flashing:(a) For low washer fluid or door/deck, check in-
puts to body controller. (b) For malfunction indicator (check engine),
check powertrain control module operation.
CONDITION: ODOMETER DISPLAY IS BLANK. THE ODOMETER VALUE IS NO LONGERRETAINED IN THIS ELECTRONIC CLUSTER.THIS TAKES PLACE IN THE BODYCONTROLLER
PROCEDURE
(1) If cluster asterisk is flashing, Refer to the Body
Chassis Diagnostic Manual to diagnose CCD Bus. (2) If cluster asterisk is not flashing, perform clus-
ter self-diagnostics. If code 921 appears in the odom-
eter display, replace body controller for odometer
failure.
8E - 34 INSTRUMENT PANEL AND GAUGES Ä

Fig. 29 Electronic Cluster Self-Diagnostic Test
Ä INSTRUMENT PANEL AND GAUGES 8E - 35

Fig. 30 Electronic Cluster Self-Diagnostic Test Continued
8E - 36 INSTRUMENT PANEL AND GAUGES Ä

CONDITION: US/METRIC MODES WILL NOT TOGGLE OR TRIP ODOMETER WILL NOTRESET
PROCEDURE
(1) Perform cluster self-diagnostics to determine if
push buttons are operational. (2) Refer to the Body Chassis Diagnostic Manual
to diagnose CCD Bus. The US/Metric toggle and trip
odometer reset are activated over the CCD Bus.
ODOMETER ADJUSTMENT
The odometer memory is no longer retained in the
cluster. This information is stored in the body con-
troller. Therefore, there is no adjustment procedure.
If the cluster is replaced odometer value will not
change. If the body controller is replaced the mileage
may be transferred using the DRB II. Refer to the
Body Chassis Diagnostic Manual for the procedure.
SWITCH AND PANEL COMPONENT SERVICE
MESSAGE CENTER REPLACEMENT
(1) Remove upper cluster bezel (Fig. 32).
(2) Remove two attaching screws (Fig. 33).
(3) Disconnect wiring connector and remove mes-
sage center. (4) For installation reverse above procedures.AIR CONDITIONING CONTROLREPLACEMENT
(1) Remove upper cluster bezel (Fig. 32).
(2) Remove two control mounting screws.
Fig. 31 Cluster Connector
Fig. 32 Cluster Bezel
Ä INSTRUMENT PANEL AND GAUGES 8E - 37

(3) Slide control rearward, disconnect cable, vac-
uum harness and electrical wiring (Fig. 34).
(4) Remove control.
(5) For installation reverse above procedures.
AUTOMATIC TEMPERATURE CONTROL LAMP REPLACEMENT
(1) Remove automatic temperature control from in-
strument panel. (2) Remove top cover screw and unsnap cover from
control (Fig. 35). (3) Remove four screws that connect computer
housing to the button housing. (4) Unsnap the button housing from the computer
housing. (5) Remove lamps by turning in a counter clock-
wise direction and install lamps by turning in a
clockwise direction. (6) For installation reverse above procedures.
When finish perform ATC system function test.
HEADLAMP AND ACCESSORY SWITCH MODULE REPLACEMENT
(1) Remove cluster bezel (Fig. 32). (2) Remove four screws attaching module to instru-
ment panel (Fig. 36).
(3) Disconnect all wiring connectors to remove
module. (4) For installation reverse above procedures.
HEADLAMP SWITCH REPLACEMENT
(1) Remove headlamp and accessory switch module
from instrument panel (Fig. 36). (2) Press button on underside of headlamp switch
and pull knob and shaft to remove.
Fig. 33 Message Center
Fig. 34 A/C Control
Fig. 35 Automatic Temperature Control Lamp
Fig. 36 Headlamp and Accessory Switch Module
8E - 38 INSTRUMENT PANEL AND GAUGES Ä