1988 PONTIAC FIERO light

-0 INSTRUMENT PANEL: GAGES CLUSTER
INDICATORS, ILLUMINATION
INTERIOR LIGHTS DIMMING
(V8 VIN F) MULTI-PORT
FUEL INJECTION (V6 VIN S) THROTTLE BODY
INJECTION (V8 VIN E)
- -
CIRCUIT

INSTRUMENT PANEL: GAGES CLUSTER
TROUBLESHOOTING HINTS COMPONENT LOCATION Page-Figure
* For a list of possible symptoms, go to System Coolant Temperature Sender (VIN E) Lower LH side of engine ....................
Diangosis. Coolant Temperature Sender (VIN F)
....................... .................... * For Instrument Cluster removal and replace- (VIN 8). Lower
LH side of engine
ment procedures, see Section 8C of the Ser- Coolant Temperature Sender (VIN S) Top LN front of engine, behind A/C Compressor.
.................. ..................... vice Manual. Fuel Tank Unit Top center of fuel tank.
..................... ...... * Try the following checks before doing the Sys- Fuse Block. Behind
LH side of IIP, below light switch.
................. tem Check. Ignition Switch. Behind IIP, on
top side of steering co
....... ........... Oil Pressure Sender (VIN E) Top rear of engine, near distributor. 1. Check GAGES Fuse by observing the . ........... Oil Pressure Sender (VIN F) (VIN 8) Top
rear of engine, near distributor.
BRAKE Warning Indicator with the Igni- Oil Pressure Sender (VIN S) ........ Lower LN side of engine .................... tion Switch in RUN and the Park Brake ................ .. el00 (42 cavities) LN
front of dash, left of brake master cylinder
applied.
................. C313 (3 cavities) Below
center of back seat. ...................
2. Check ground 6200. . 6118 (VIN F) (VIN 8) ............. Rear of RN cylinder head. ...................
.................... ................... 3. Check case ground of Coolant Temperature 6118
(VIN S) Rear
of RH cylinder head.
.......................... ............ Sender. 6200 Behind I/P, left of steering column ' h .......................... 4. Check case ground of Oil Pressure Sender. 6304 Under rear seat,
on support bracket
.......................... S204. IIP harness, behind instrument cluster. ........ 5. Check Indicator bulbs. .......................... ........ S205. I/P harness, behind instrument cluster. * Go to System Check for a guide to normal .......................... S217. I/P harness, behind center of IIP .............. operation.
* Go to Systern Diagnosis for diagnostic tests.
SYSTEM CHECK
* Use the System Check Table as a guide to
normal operation. Refer to the diagnosis given
if other results occur.
* Tests follow in System Diagnosis.

SYSTEM CHECK TABLE
FASTEN BELTS Indicator
lights for
6 to 8 seconds
See
Symptom Table
Oil Pressure Gage indicates
See
Syqtom Table
Coolant Temperature Gage
Voltmeter indicates Battery
Oil Pressure Gage indicates
See Symptom Table
engine oil pressure
L
Go to System Diagnosis for a list of symp-
toms.
SYSTEM DIAGNOSIS
Do the tests listed for your symptom in the
Symptom Table below, or when directed
by
the System Check.
r For Instrument Cluster removal and replace-
ment procedures, see Section
8C of the Ser-
vice
Manual.
Tests follow the Symptom Table.
SYMPTOM TABLE
I SYMPTOM 1 IFORDlAGMOSlS I
Fuel Gage indicates
EMPTY when there
is fuel in the tank
Fuel Gage indicates
FULL or beyond at
all times Do
Test
C: (Also see
Test
B terrnind PO)
Do Test D: (Nso see
Test
B terIllinal PO)
Fuel Gage is
inaccurate
Coolant
Temperature Gage
indicates NOT with
engine coolant cool
and Ignition Switch
in RUN Do
Test E: (Also see
Do Test F (Also see
Test B terminal
2)
coolant
Temperature Gage
indicates COLD at
all times Do
Test
6: (Also see
Test
B terminal 2)
Coolant Do Test N: (Also see
Temperature Gage
Test
B terminal 2)
is inaccurate
(Continued on next page)

INSTRUMENT PANEL: GAGES CLUSTER
I Oil Pressure Gage
(Continued from previous page)
indicates low
pressure
and oil
pressure is good
Coolant
Temperature Gage
does not indicate
HOT with Ignition
Switch in START or
BULB TEST, but
does operate
accurately
Do Test I: (Also see
Test A
terminal B)
Check DK GRN (35)
wire and Ignition
Switch for opens
Repairlreplace as
necessary
Oil Pressure Gage
indicates high
pressure at
all times
and oil pressure is
good Do
Test
J: (Also see
Test A terminal
8)
Oil Pressure Gage is
inaccurate Do
Test K: (also see
Test A terminal
8)
Do Test L
Tachometer does not
operate
Speedometer1
Odometer is
inaccurate Do
Test M
Do Test N: (with
5-33431-873 harness
connector available)
One or both
Odometers do not
operate properly,
but Speedometer
operates accurately
I
Check the
Instrument Cluster
Printed Circuit for
cracks or flaws
Replace the
Speedometer1
Odometer Assembly
(Continued in next column) (Continued from previous
column)
Hi Beam Indicator
does not operate
properly See
Exterior lights
Section 8A-110
(Also see Test
B
terminal 8)
I operate properly
I
(Also see Test A
I
Seatbelt Indicator
and alarm do not
BRAKE Warning Indicator does not
work properly
I
See Warnings and
Alarms (see Index)
SERVICE
ENGINE SOON
Indicator does not
does not work See
Brake Warning
System, Section
8A-41 (Also, see
Test A terminal
1)
See Section 6E of
1 Service Manual
Do Test O
r
(Also, see Test B
terminals 7 and
9)

INSTRUMENT PANEL: GAGES CLUSTER I i
B: CONNECTOR 62 PINOUT TEST
0 IGNITION SWITCH IN RUN EXCEPT
FOR RESISTANCE
MEASUREMENTS
0 MEASURETO GROUND UNLESS
ANOTHER TERMINAL IS GIVEN
0 CLUSTER CONNECTOR 62 AS
SEEN FROM THE DRIVER'S SEAT
WlTH THE INSTRUMENT CLUSTER
REMOVED
IF THE CORRECT VOLTAGE OR
RESISTANCE IS FOUND AT THE
TERMINAL, AND THE CLUSTER
FUNCTION THAT USES THOSE
TERMINALS DOES NOT OPERATE.
CHECK WIRES, BULBS, AND
PRINTED CIRCUIT. IF OK. REPLACE
EITHER THE GAGE OR THE INSTRUMENT CLUSTER (SEE
SECTION 86)
IF THE CORRECT VOLTAGE OR
RESISTANCE IS NOT FOUND AT A TERMINAL, DO THE TEST GIVEN
OR GO TO THE PAGE REFERRED VEHICLE
SPEED SIGNAL
NOT USED INSTRUMENT
CLUSTER ILLUMINATION. VARIABLE
VOLTAGE
WlTH HEAD OR PARK LIGHTS ON AND 11 DIMMER CONTROL ADJUSTED. SEE SECTION I

INSTRUMENT PANEL: GAGES CLUSTER
Speedorneter and Odometers
The Speedometer is operated by an electronic
circuit. The Vehicle Speed Sensor (VSS),
located in the transmission, generates an AC
voltage whose frequency is proportional to the
speed of the vehicle. This goes to the Vehicle
Speed Sensor Buffer and then to the Speedom-
eter circuit board in the Instrument Cluster.
The Solid State circuit drives the pointer of the
Speedometer. There is no speedometer cable
in
the vehicle.
The same speed signal from the Vehicle Speed
Buffer is processed by the Speedometer circuit
board to drive the Odometers. They are oper-
ated by a motor that responds to pulses from
the Speedometer circuit.
UpshiN Indicator
With Manual Transmission, the indicator
lights when the car should be shifted to the next
higher gear for better fuel economy. Battery
voltage is applied to one side of the bulb. The
other side of the bulb is switched to ground by
the ECM which uses engine data to compute an
efficient shift point.

INSTRUMENT PANEL: DIGITAL CLUSTER a
TROUBLESHOOTING HINTS COMPONENT LOCATION u Page-Figure
0 For a list of symptoms and their diagnosis. go
to System Diagnosis
.
0 For Instrument Cluster removal and replace-
ment procedures see Section
86 of the Ser-
vice Manual
.
* Try the following checks before doing the
System Check
.
1 . Check the CLSTR Fuse .
2 . Check the CTSY Fuse .
3 . Check the TAIL Fuse .
Coolant Temperature Sender (VIN E) Lower LH side of engine ....................
Coolant Temperature Sender (VIN F)
(VIN 8)
........................ Lower LH side of engine ....................
Fuel Tank Unit .................. Top center of fuel tank ......................
Fuse Block ...................... Behind LH side of IIP. below light switch .......
Ignition Coil (VIN E) ............. Top center rear of engine ....................
Ignition Coil (VIN F)(VIN 8) ....... RH rear side of engine ......................
Ignition Switch .................. Behind IIP. on top side of steering column ......
Oil Pressure Sender (VIN E) ....... Top rear of engine. near distributor ............
Oil Pressure Sender (VIN F) (VIN 8) . Top rear of engine. near distributor ............
Oil Pressure Sender (VIN S) ........ Lower LH side of engine ....................
................ .. 4 . Check the GAGES Fuse . el00 (42 cavities) LH
front of dash. left of brake master cylinder 201- 0-A
C114
(1 cavity) (VIN E) ............ Taped to engine harness. above rear of engine
5 . If more than one indicator is out. check the C114 (1 cavity) (VIN F) (VIN 8) ..... Taped to engine harness. above rear of engine ... 201- 7-B
battery voltage inputs . . C207 (15 cavities) ................ Behind RH side of IIP near ECM ............. 201-13-A
................. .................... * Go to System Check for a guide to C313 (3 cavities) Below
center of back seat 201- 9-C operation . 6118 (VIN F) (VIN 8) ............. Rear of RH cylinder head .................... 201- 5-A
0 Go to System Diagnosis for diagnostic tests . 6200 .......................... Behind IIP. left of steering column ............ 201-10-A
6304
.......................... Under rear seat. on support bracket
SYSTEM CHECK S143 (VIN F) (VIN 8) ............. Engine harness. RH front of dash ............. 201- 6-A
0 Use the System Check able as a guide to S201 ........................... IIP harness. behind instrument cluster ......... 201-10-A
normal operation . Refer to the diagnosis S203 ........................... I/P harness. behind instrument cluster ......... 201-10-A
........................... ......... given if other results occur . S204 IIP harness. behind instrument cluster 201-10-A
........................... ......... Tests follow in System Diagnosis . S205 IIP harness. behind instrument cluster 201-10-A
S217 ........................... IIP harness. behind center of IIP .............. 201-10-A
S225 ........................... IIP harness. behind instrument cluster ......... 201-10-A
(Continued on next page)

INSTRUMENT PANEL: DIGITAL CLUSTER 1 fE!
SYSTEM CHECK TABLE
FOR DIAGNOSIS
Do Tests A and B
Check
all Ignition Power Inputs and grounds
Replace the Instrument Cluster (See Section
8C)
ACTION
Turn the Ignition Switch to RUN
Observe and press it again
Replace the Instrument Cluster (See Section
8C)
The Speedometer indicates the correct vehicle
The Fuel, Oil pressure, Coolant Temperature and
Volt displays indicate the correct values I I I
NORMAL RESULT
All displays light up at full intensity for 2
seconds including Speedometer, Tachometer,
Fuel, Oil Pressure, Coolant Temperature, and
Battery voltage
Bar graphs (Tachometer, Fuel) run up to the
maximum and back again and then display their
present readings
All other displays use a segment pointer that
runs from bottom to top and back again and
then displays their present readings
Segments of the bar graphs that are not fully
illuminated, are
lit up faintly and are visible