PONTIAC FIERO 1988 Service Repair Manual

INSTRUMENT PANEL: GAGES CLUSTER
GAGES TACHOMETER

3 INSTRUMENT PANEL: GAGES CLUSTER
GAGES, SPEEDOMETER
FUSE - BLOCK
OHMS
AT FULL
OHMS AT EMPTY
- - - - - -

INSTRUMENT PANEL: GAGES CLUSTER I e
CLUSTER REAR VIEW
CONNECTOR 62
-
BULB LOCATIONS
CONNECTOR Cl
TEST POINTS CONNECTOR Cl
A Illumination TP1 Oil Pressure Gage Sender 1
B BRAKE Warning Indicator TP2 Temperature Gage Sender 2
C Not Used TP3 Fuel Gage Sender 3
D Illumination TP4 Tachometer Sender 4
E Illumination TP5 Speed 5
F SERVICE ENGINE SOON Indicator
6
G Not Used 7
H Illumination 8
I Fasten Belts Indicator 9
J Illumination 10
K Illumination 11
L RH Turn Indicator 12
M LH Turn Indicator 13
N Hi Beam Indicator 14
O Illumination
P Illumination
Q Illumination
R SHIFT Indicator Tachometer Sender
Ground
Illumination
Not Used
Temperature Gage Sender
Not Used
Open
Oil Pressure Gage Sender
Ignition
Not Used
Not Used
Ground
Fasten Belts
Speedometer
CONNECTOR 62
1 BRAKE Warning Indicator
2 Ground
3 Illumination
4 Open
5 Open
6 Open
7 LH Turn Indicator
8 Hi Beam Indicator
9 RH Turn Indicator
10 Fuel Gage Sender
11 Not Used
12
470R to Generator
13 SERVICE ENGINE SOON Indicator
14 SHIFT Indicator

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 P
A: CONNECTOR 61 PINOUT TEST
a MEASURETO GROUND UNLESS
ANOTHER TERMINAL IS GIVEN
CLUSTER CONNECTOR Cl AS SEEN
IGNITION IS
SWTCHED TO RUN. SEE
FROM THE DRIVER'S SEAT WITH SECTION 8A-75.
* IF THE CORRECT VOLTAGE OR
RESISTANCE IS FOUND AT THE
TERMINALS, 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
NOT USED
NOT USED
260°F
(130°C)T0 1260 OHMS AT 100°F (40°C). DO

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 I P
C: FUEL GAGE ALMYS lNDlCPaTES
FULL
Disconnect the Fuel Tank Sender Unit connec-
tor. Turn Ignition Switch to RUN.
If the Fuel Gage now indicates FULL,
repairlreplace Fuel Gage Sender.
@ If the Fuel Gage still indicates EMPTY,
check PNK (30) wire (see schematic) for a
short to ground. Check the Instrument Clus-
ter Printed Circuit for flaws and the gage
connections. Replace Fuel Gage if the PNK
(30) wire, Printed Circuit, and gage connec-
tions are OK, (see Section 8C).
D: FUEL GAGE ALVVAYS lNDlCATES
EMPTY
At: FUEL TANK SENDER UNIT CONNECTOR
(HARNESS HALF)
(Disconnected)
1. Checklrepair PNK (30) wire (see sche-
matic) for an open. Check Instrument
Cluster Printed Circuit for flaws and for
clean and tight Fuel Gage connections.
Replace Fuel Gage if the above checks are
OK (see Section
8C).
2. Check BLK (150) wire for an open to
E: FUEL GAGE ACCURACY TEST
Disconnect the Fuel Tank Sender Unit connec-
tor and connect one red lead of
5-33431 tester to
terminal
B (PNK) and the other to te
(BLK) of the harness half of the connector. Set
the resistance dials of the tester to 0 ohms, 44
ohms and then to 90 ohms. The Fuel Gage
should read E,
I12 and then F.
If Fuel Gage responds correctly, replace
Fuel Gage Sender and its wires.
0 If Fuel Gage does not respond correctly,
check PNK (30) wire to the Instrument Clus-
ter Printed Circuit and BLK (150) wire for
high resistance. Also, inspect the Printed
Circuit for proper mating of connectors.
Replace the Fuel Gage if the wires and
Printed Circuit are good.
F: COOLANT TEMPERATURE GAGE
ALWAYS
INDICATES HOT
Disconnect the Coolant Temperature Sender
connector and place Ignition Switch in RUN.
@ If Coolant Temperature Gage reads cold,
replace the Coolant Temperature Sender.
0 If the Coolant Temperature Gage does not
read cold check DK GRN (35) wires and Igni-
tion Switch, terminal
61 of connector Cl for
a short to ground (see schematic). Replace
the Coolant Temperature Gage if
all are good
(see section
8C).
6: COOLANT TEMPERATURE GAGE
ALWYS INDICATES COLD
Disconnect the Coolant Temperature Sender
connector and jumper the DK GRN (35) wire to
ground. Put the Ignition Switch in RUN.
0 If the Coolant Temperature Gage reads hot,
replace the Coolant Temperature Sender.
If the Coolant Temperature Gage does not
read hot, check DK GRN (35) wire for
an
open. Replace the Coolant Temperature
Gage if the wire is good (see Section
8C).
H: COOLANT TEMPERATURE GAGE
ACCURACY TEST
Disconnect the Coolant Temperature Sender
connector. Connect one red clip lead of the
5-33431 tester to the harness connector DK
GRN (35) wire and the other red clip lead to
ground. Adjust the resistance dials of the tester
to 1254 ohms,
697 ohms and then to 54 ohms.
The Coolant Temperature Gage should show
100°F
(40°C), 220°F (100°C) and then 260°F
(130°C).
If the gage reads correctly, the wiring and
gage are good. Replace the Coolant Tem-
perature Sender.
If the gage is not correct check DK GRN (35)
wire and Printed Circuit. If they are good,
replace the Coolant Temperature Gage (see
Section
8C).

INSTRUMENT PANEL: GAGES CLUSTER
I: OIL PRESSURE GAGE ALWAYS
lEUDlCATES ZERO
At: OIL PRESSURE SENDER
Condition:
lanition Switch: RUN
Action
I Correct Result I For Diagnosis
If the result is correct, replace the Oil
Pressure Sender.
1. Check TAN (31) wire to Instrument Clus-
ter for a short to ground. Check Instru-
ment Cluster Printed Circuit for cracks or
flaws. Repairlreplace the Oil Pressure
Gage if the wire and Printed Circuit are
OK (see Section
86).
Disconnect Oil
Pressure
Sender
J: 81L PRESSURE GAGE ALWAYS
INDICATES
HBGH PRESSURE
(Disconnected)
high pressure
connector
Oil Pressure
Gage shows (Continued
from previous column)
See 1
Cluster Printed Circut for an open. If wire
K: OIL PRESSURE GAGE ACCURACY
TEST
Disconnect the Oil Pressure Sender. Connect
one red clip of the
5-33431 tester to the harness
connector, TAN (31) wire, and connect the other
red clip lead to ground. Set the resistance dials
of the sender to 0 ohms, 43 ohms and then to 90
ohms. The Oil Pressure Gage should read 0 psi
(0
Wa), 40 psi (280 kPa) and 80 psi (660 kPa)
with the V6 or 0 psi (0 kPa), 30 psi (210 kPa) and
60 psi (420
kPa) with the V8.
r If the gage reads correctly, replace the Oil
Pressure Sender.
@ If the gage does not read correctly, check the
TAN (31) wire and Printed Circuit. If they
are good, replace
the Oil Pressure Gage (see
Section 89.
L: VOLTMETER TEST
With the Ignition Switch in RUN, connect a
Voltmeter between the positive and negative
als of the Battery.
If the voltage reading on the test voltmeter
is
approfimately the same as the car's Volt-
meter, the car's Voltmeter is OK. If
the voltage reading on the test voltmeter
is different
from the car's Voltmeter, check
the Instrument Cluster Printed Circuit for
cracks or flaws. Repairlreplace the Volt-
meter if
all wires and Printed Circuit are OK
(see Section 8C).
M: TACHOMETER TEST
At: INSTRUMENT CLUSTER PRINTED
CIRCUIT CONNECTOR 61
(Disconnected)
Condition:
I @ Ignition Switch: RUN I --
For Diagnosis
Of incorrect
Between Results
1 (WRT) & Greater than See Ground 10 volts
@ If above voltage is corred, replace the
Tachometer.
1. Check WHT (121) wire md Tachometer
Filter to
Ignition Coil (see schematic). If
wire is OK, see Section 6D for further
diagnosis.
N: SPEEDOMETER TEST
1. Disconnect connector C207. Connect the
5-33431 tester to the harness half of the con-
nector,
terminal C (LT GRN) and to ground,
using the
5-33431-873 harness connector or
equivalent. With the tester set to ON, 54
mph, 60
HZ and the Ignition Switch in RUN,
the speedometer should read 54 mph
+ 2
mph.
(Continued
in next column)
(Continued on next page)