1988 PONTIAC FIERO light

install or Connect Adjust
1. Retaining ring e Headlight aim
2. Electrical connector
3. Headlight
4. Retaining spring
LICENSE PLATE LIGHT
Fig. 8B-7
5. Bezel Assembly or Bulb Replacement
6. Four screws into bezel
7. Lower headlight Remove or Disconnect
8. Close hood 1. License plate

88.8 LIGHTING SYSTEMS AND HORNS
2. Two screws
3. Light assembly
4. Socket from assembly
5. Bulb from socket
Install or Connect
1. Bulb into socket
2. Socket into assembly
3. Assembly
4. Two screws
5. License plate
1. ATTACHING NUT
2. LAMP A98EMBLV
Fig. 88-8 Rear Tail/Stop/Turn Signal Lights
REAR TAIL/STOP/TURN SIGNAL LIGHTS
Fig. 8B-8
Replacement Bulb: Trade No. 2057, 32/2
Candlepo wer
Remove or Disconnect
1. Open hatch
2. Fasteners at trim panel
3. Trim panel
4. Wing nuts holding taillight lens
5. Taillight lens
6. Bulb from socket
Install or Connect
1. Bulb into socket
2. Taillight lens
3. Wing nuts
Adjust
Taillight lens for proper appearance before
tightening wing nuts
4. Trim panel
5. Fasteners
6. Close hatch
Fig. 88-9 Rear Sidemarker Lights
SIDEMARKER LIGHTS
Figs. 88-4 (Front) and 8B-9 (Rear)
Assembly Replacement - Front
Remove or Disconnect
1. Six screws from filler panel under front fascia
2. Filler panel
3. Socket from assembly
4. Two retainers
5. Assembly
Install or Connect
1. Assembly
2. Two retainers
3. Socket
4. Filler panel
5. Six screws
Assembly Replacement - Rear
Remove or Disconnect
1. Open hatch
2. Fasteners at trim panel
3. Trim panel
4. Socket from assembly
5. Two nuts
6. Assembly
Install or Connect
1. Assembly
2. Two nuts
3. Socket
4. Trim panel
5. Fasteners
6. Close hatch

LIGHTING SYSTEMS AND HORNS 8B-9
Bulb Replacement - Front
Replacement Bulb: Trade No. 194, 2
Candlepower
Remove or Disconnect
1. Six
screws from filler panel under front fascia
2. Filler panel
3. Socket from assembly
4. Bulb from socket
Install or Connect
1. Bulb into socket
2. Socket into assembly
3. Filler panel
4. Six screws
Bulb Replacement - Rear
Replacement Bulb: Trade No. 194, 2
Candlepower
Remove or Disconnect
1. Open hatch
2. Fasteners at trim panel
3. Trim panel
4. Socket from assembly
5. Bulb from socket
Install or Connect
1. Bulb into socket
2. Socket into assembly
3. Trim panel
4. Fasteners
5. Close hatch
TURN SIGNAL FLASHER
The turn signal flasher is in the convenience
center, behind the instrument panel to the right of the
steering column. To remove the flasher, lift it up and
out.
UNDERHOOD LIGHT
Replacement Bulb: Trade No. 93, 15
Candlepower
Remove or Disconnect
1. Open hood
2. Bulb from socket
Install or Connect
1. Bulb into socket
2. Close hood
HORNS
If the horns do not blow, or blow constantly,
follow the diagnostic procedures in Section
8A.
Fig. 88-10 Horns
Horn Tone Poor
1. Horn Tone Poor - Tighten bolts in mounting
area, or correct poor connections or ground.
2. Low-Pitched
Moan
- Sounds like "mooing."
Caused by current too high. Adjust current (see
the following).
3. Weak Tone - Current too low. Correct poor
connections or ground, or adjust current (see the
following).
.4. Weak, Strained Tone
- Remove foreign
object in horn.
5. Harshvibration-Bendbracketsohornisnot
touching sheet metal.
Current Adjustment
Current draw for a horn while operating should
be 4.5 to 5.5 amperes at 11.5 to 12.5 volts. High current
(more than 20 amperes) indicates an overheated
winding or
shorted horn; replace the horn. A current
reading of about
18 amperes means the contact points
are not opening; adjust the horn current (see the
following).
No current reading indicates a broken
connection, or
an open circuit due to a broken lead or
overheated horn. An overheated horn must be
replaced. No current reading may also mean the
contact points are open; adjust the horn (see the
following).

Adjust 2 . Filler panel 3 . Electrical connector
1 . Increase Current - Turn adjusting screw 4 . ~~l~/~~~~~
clockwise 5 . Horn
2 . Decrease Current . Turn adjusting screw
counterclockwise
Install or Connect
3 . Current adjustments should be made 1/4 turn
(90") at a time
Horn Assembly
Remove or Disconnect
1 . Six screws from filler panel behind front fascia on
driver's side 1
. Horn
2 . Bolt/screw
3 . Electrical connector
4
. Filler panel
5 . Six screws
Horn Relay
The horn relay is in the convenience center.
behind the instrument panel to the right of the steering
column
. To remove the relay. pull it straight out .
REPLACEMENT LIGHT BULBS
For exterior light replacement procedures. see the rest of this
section
. For interior light replacement procedures. see Section $A
and Section 8C .
EXTERIOR LIGHTS Trade No . ...................................................................................................................... Back-up Lights 1 156
Center
High-Mounted Stoplight ............................................................................................. 577
Front Barking/Turn Signal Eights ..................................................................................... 2057
Fog Lights
............................................................................................................................... H-3
Headlights ....................................................................................................................... H6054 ................................................................................................................ License Plate Lights 194
.................................................................................... Rear Tail/Stop/Turn Signal Lights 2057
Sidemarker Lights (Front and Rear) ...................................................................................... 194 ..................................................................................................................... Underhood Light 211
BNTERBOR LIGHTS Trade No .
......................................................................................... Air Conditioner/Heater Controls 194 .................................................................................................................. Ashtray & Lighter 194 .............................................................................................................. Cargo Compartment 561
................................................................................................ Cluster & Speedometer (Tach) 194 ..................................................................................................................... Console Ashtray 194 ............................................................................................................. Console Compartment 194
Courtesy Lights
..................................................................................................................... 194 ......................................................................................................................... Dome Light 561
Gear Selector Indicator
............................................................................................................ 74 .......................................................................................... Headlight High-Beam Indicator 194
Indicator Lights
..................................................................................................... Brake System Warning 194
With Gages
........................................................................................................................ 74
............................................................... Charging System Warning (except Rally Gages) 194 .................................................................................................................... Choke Warning
194
With Gages
........................................................................................................................ 74
...................................................................... Oil Pressure Warning (except Rally Gages) 194 ............................................................................................................ Seat Belt
Reminder 194
With Gages
.................................... ... ................................................................................. 74 ............................................................................................. Service Engine Soon Warning 194
With Gages
..................................................................................................................... 74 ............................................................ Temperature Gage Warning (except Rally Gages) 194
........................................................................................................................ Reading
Light 906 ............................................................................................................ Turn Signal Indicators 194

LIGHTING SYSTEMS AND HORNS 8B-11
2-HORN LEADS 3-SIDE MARKER
4-HEADLAMP
%-TURN SIGNAL PARK LAMP
6-HEADLAMP MOTOR RELAY
7-HEADLAMP MOTOR JUMPER
8 -HEADLAMP ISOLATION RELAY
9- BRAKE PRESS. WARNING SW.
10-TO
SIDE MARKER
11-HORNS
12-TO
HEADLAMP
13-ENGINE HARNESSCONNECTOR
14-BULKHEAD CONNECTOR
15-CONNECTOR END CAP
16-HEADLAMP MOTOR ISOLATION RELAY
Fig. 8B-1 1 Forward Light Wiring

INSTRUMENT PANEL, GAGES & CONSOLE 8C-'I
SECTION 8C
NSTRUMENT PANEL, GAGES & CONSOLE
CONTENTS
General Description ................................... 8C-1
Instrument Panel and Gages ........................ 8C-1
Printed Circuit .......................................... 8C-1
Instruments ................................................... 8C- 1
Speed Sensors
............................ .. ............. 8C- 1
Pinion Gear
............................................. 8C-2
Photo Speed Sensor ................................ 8C-2
PM Generator ................... .. ...... ............... 8C-2
Speedometer ................................................ 8C-2
Mechanical ....................... .. .................... 8C-2
Quartz ........................ .. .......................... 8C-2
Digital .................... .. ...... ................. 8C-2
Fuel Gage .................................................... 8C-2
Temperature Warning Light ...................... 8C-3
Generator Warning Light ............................ 8C-3
Engine Oil Pressure Light ............................ 8C-3
"Service Engine Soon" Light ....................... 8C-3
Upshift Indicator Light .............................. 8C-3
Diagnosis .................... .. ........................... 8C-3
General Information .................................. 8C-3
Instrument Panel & Gages ...................... ..... 8C-3
On-Car Service ......................... .. ........... 8C-4
Instrument Panel Pad ................................... 8C-4
Instrument Panel Cluster ........................... 8C-4
Instrument Panel Carrier ............................. 8C-4
Headlight Switch .......................................... 8C-4
Console Mounted Switches and
Accessories
............................................... 8C-4
Console ......................................................... 8C-4
Speedometer .................................................. 8C-5
Illustra3ions ................................................. 8C-5
IP Pad ........................................................... 8C-5
IP Carrier ................................................... 8C-6
Instrument Cluster ....................................... 8C-6
Lower IP Covers ......................................... 8C-7
IP Trimplates ............................................... 8C-7
IP Hush Panels; with A/C .......................... 8C-8
..................... IP Lower Trim Pad (Console) 8C-8
Map Holder or Map Pocket ........................ 8C-8
IP Hush Panels; without A/C ..................... 8C-9
Radio Mounting ........................................... 8C-9
Subwoofer & Hatch Release
Switches/Covers ........................................ 8C- 10
Foglamp Switch/Cover ................................ 8C- 10
Oil Pressure and Temperature
Switches
..................................................... 8C-11
Heater/Ventilation/Defroster
Ductwork .................................................. 8C- 12
A/C and Defroster Ductwork ..................... 8C-13
Ram Vent System Ductwork ....................... 8C-14
Console Mounted Switches
&
Accessories ................................................. 8C- 14
Dash Insulators
............................................ 8C- 15
Heater Floor Outlet
..................................... 8C-15
................ Headlamp/Parking Lamp Switch 8C- 15
............. Dash Mounted Accessory Switches 8C- 15
GENERAL DESCRIPTION
INSTRUMENT PANEL AND GAGES
INSTRUMENTS
Instruments consist of fuel gage, temperature
The instrument panel on most cars is a sing,e unit indicator light, generator light, oil pressure indicator
design and all parts attach to the main instrument light, and speedometer. See Section 9F for optional
panel with clips and screws. To service the instrument Gages and tachometer. Service on instruments
panel and components see on-car service information, can be obtained through authorized repair stations.
However, knowledge of instrument circuit checks will
PRINTED CIRCUIT
All models are equipped with printed circuits
which supply current to most instrument panel lights
and instruments. These circuits are made of copper foil
which is die cut and bonded to a polyester base film
(usually mylar). The printed circuit electrical power is
supplied by a connector containing several wires, as
shown in the instrument panel wiring harness
installation instructions. The connector also helps
retain the printed circuit to the speedo cluster. The rest
of the circuit is retained by additional connectors (if
used) and snap-in
bulbs/sockets. For individual
printed circuit diagrams, see Section
8A-80/8 1/82/83,
'Instrument Panel'. help
in determining if operating difficulties lie in the
instrument itself or its related circuit.
Instruments have been designed for easy removal
by elimination of separate wiring. With the wiring
provisions integrated with the instrument panel wiring,
the instruments can be removed after removing the
trim and lens.
SPEED SENSORS
There are three speed sensors currently in use:
1. PINION GEAR; used in mechanical systems
2. PHOTO SPEED SENSORS; used in mechanical
systems
3. PM GENERATOR; used in electronic systems

842-2 INSTRUMENT PANEL. GAGES & CONSOLE
Pinion Gear
The PINION GEAR is attached to the
traaasmission/transaxle output shaft and rotates in
proportion to the speed of the car. This rotation is
transferred from the pinion gear to the speedometer
head by the speedometer cable.
Photo Speed Sensor
On vehicles that use a mechanical drag-cup
speedometer, the PHOTO SPEED SENSOR is
inserted into the frame of the mechanical speedometer
to provide an electrical feedback to the ECM that
represents vehicle speed. The ECM needs to know how
fast the car is traveling in order to control and operate
the cruise control, cooling fan, and transmission and
evaporative systems.
The photo speed sensor is made up of two special
electronic devices: a Eight-Emitting Diode (LED) and
a photo transistor (a light-sensitive amplifying device).
In the mechanical speedometer, there is a reflective
blade attached to the rotating magnet that is polished
to
reflect light from the LED back to the photo
transistor. Whenever the light strikes the photo
transistor, it conducts electricity. The rate that the
transistor conducts and does not conduct is
proportional to the speed of the magnet, which reflects
the speed of the vehicle. This voltage signal from the
photo transistor is sent to a buffer amplifier (part of the
speed sensor) to be conditioned to a signal the ECM
can understand and use.
PM Generator
The PM (Permanent Magnet) GENERATOR is
a small
AC generator used to sense vehicle speed. The
shaft of the generator fits into a pinion gear in the
transmission/transaxle output shaft (as does the cable
in
a mechanical system).
When the output shaft rotates, the magnet rotates
and generates a voltage. Except for the permanent
magnet, the
PM Generator is exactly like a miniature
alternator. The PM generator is constructed to provide
a voltage whose frequency is about
1.1 cycles per
second for every mile per hour of vehicle speed. This
signal is sent to a buffer amplifier, and then to the
speedometer and the
EGM.
SPEEDOMETER
The speedometer is a road speed indicator with
an odometer to record total mileage, and, on some cars,
a resettable trip odometer.
The major types of speedometers in use are
mechanical instruments and electronic instruments.
Mechanical speedometers use a dial needle to indicate
road speed. Electronic speedometers include
instruments that use a dial indicator and those using
bar-graph
LCD's (Liquid Crystal Displays) or VTF
(Vacuum Tube Fluorescent) displays.
Meehanice! Speedometers
A mechanical speedometer uses a cable driven
(through a pinion gear) by the transmission output
shaft. The cable connects to a magnetic drag-cup inside the
speedometer, which rotates the speedometer
needle. The end of the rotating cable causes a small bar
magnet to rotate within a metal cup. As the magnet
rotates within the cup, it magnetically attracts (drags)
the metal cup along behind it. Two things work to
prevent the cup from rotating as quickly as the magnet.
1. The distance of the magnet from the cup reduces
its effect on the cup.
2. A counterspring is wound around the shaft of the
cup in such a way as to oppose the normal
rotation of the cup. The counterspring loads the
drag-cup to give correct indication of the speed,
prevent needle overshoot, and also to return the
drag cup to a zero point.
Mechanical speedometers require a photo speed
sensor to provide road speed information for the ECM
and other systems, such as Cruise Control and the TCC
(Torque Converter Clutch).
The odometer on these instruments consists of
numbered wheels that are rotated by the speedometer
cable through worm gears.
Quartz Speedometer
The quartz speedometer is an electrically driven
instrument. The indicator needle is driven by a
precision DC motor, and is countersprung to provide
a mechanical load, prevent overshoot of the needle, and
return the indicator to zero when the road speed is
zero.
The source of speed information for a quartz
speedometer is the PM generator. From the PM
generator, speed information goes to the buffer
amplifier to be converted to digital voltage, and then
to the cluster circuitry, which interprets the speed of
the vehicle and produces small voltage to apply to the
speedometer motor.
The odometer on this instrument consists of
numbered wheels that are electrically driven by a
special precision DC motor called a stepper motor.
Digital Speedometer
Digital clusters utilize two types of displays: LCD
(Liquid Crystal Display) and VTF (Vacuum Tube
Fluorescent). They are used in digital speedometers
and bar-graph tachometers, fuel gages, etc.
Speed information entering the cluster from the
buffer amplifier is interpreted by a microcomputer
which controls the speed indication, the tachometer
display and the odometer reading.
The odometers associated with these instruments
utilize either numbered wheels driven by a small motor
or electronic displays. With an electronic display, the
mileage reading is stored in a computer chip (called a
non-volatile RAM chip; NVRAM) that does not
become 'erased' when the vehicle is turned off,
as the
display does not retain the information.
FUEL GAGE
An electrical fuel gage is used on all models,
consisting of an instrument panel gage and a fuel tank
pick-up. The fuel gage indicates the quantity of fuel in

INSTRUMENT PANEL. GAGES & CONSOLE 8C-3
tank only when ignition switch is turned to "ON" or
"ACCESSORY" positions.
When ignition is turned to "OFF" or "START"
positions, the pointer may come to rest at any position.
The letters
"E" and "F" on the fuel gage are used to
point out direction of indicator travel only.
TEMPERATURE WARNING LIGHT
The engine temperature warning light is
controlled by a thermal switch which senses engine
coolant temperatures.
When the ignition switch is turned to "START"
position, a test circuit is closed and the light will come
on to indicate whether the light is functioning properly.
It is important to note that with low boiling-point
coolants (such as plain water) the temperature light
may not come on even though the coolant is boiling.
GENERATOR WARNING LIGHT
The generator warning light, located in the
instrument cluster, should come on when the ignition
switch is turned
"ON" and engine is not running. If
not, either the bulb is burned out or wiring to generator
has an open circuit.
When the generator voltage output becomes
greater than the battery voltage, the
"GEN" light
should go out. This does not, however, indicate
whether the battery is being charged or if the voltage
regulator is functioning properly.
Checks of the charging system are covered in
Section 6D, 'Engine Electrical'.
ENGINE OIL PRESSURE LIGHT
The engine oil pressure warning light is mounted
in the instrument cluster and controlled by a pressure
operated switch located on the engine block. When the ignition switch is
in the
"run" or "start9' position, the
oil pressure light should come on. If not, the bulb is
burned out, there is an open circuit between the bulb
and the oil pressure switch, or there is an open circuit
between the oil pressure switch and the choke heater.
After the engine is running, the oil pressure light
should go out when the oil pressure reaches the correct
specification. If not an oil pressure problem, a faulty oil
pressure switch or an open circuit from the choke
heater fuse to the oil pressure switch is indicated.
"SERVICE ENGINE SOON" LIGHT
All cars have a "SERVICE ENGINE SOON"
light mounted in the instrument cluster. The
"SERVICE ENGINE SOON9' light should come on
during engine starting. The light may stay on
a short
time after the engine starts.
If the light comes on while
driving, service to the emission control system may be
required. See Section
6E and Section 8A-80,
'Instrument Cluster', for complete diagnosis and
wiring diagrams of the
""P;RVICE ENGINE SOON"
light circuit.
UPSHIFT INDICATOR LIGHT
If your vehicle has a manual transmission, there
may be an
''Upshift" light on the instrument panel.
This light is illuminated to indicate optimum shift
points throughout the range from optimum fuel
economy to optimum performance. When this light is
on, shift your transmission to the next higher gear
range if conditions permit. For fuel economy,
accelerate slowly and shift when the light goes on. For
performance, accelerate as desired and shift when the
light goes on.
Safe operation of the vehicle may require shifting
differently than indicated by the "Upshift" light to
adapt to weather, road or traffic conditions.
Downshifting one or more gears may be required
to keep the engine running smoothly or to maintain
satisfactory performance.
DIAGNOSIS
Diagnostic information for all instrument panel
electrical systems is found in Section
8A-80,
'Instrument Panel'.
CAUTION: When removing or
installing any electrical units,
disconnect the negative battery cable
to prevent possible short circuits
which could lead to personal injury
and/or property damage. When
replacing a speedometer or
odometer assembly, the law requires the
odometer reading of the replacement unit to
be set to register the same mileage as the
prior odometer.
if the same mileage cannot be
set, the
law requires that the replacement
odometer be set to zero and a label be
installed on the driver's door frame to show
the previous odometer reading and the date
of replacement.
GENERAL BNFORMATlOM
INSTRUMENT PANEL AND GAGES
The instrument panel is a single unit design and
and screws. To service the instrument panel and
all parts attach to the main instrument panel with clips components see Figs. 601 through 610.