
ENGINE-ELECTRICAL 6Y-9
63 AMP 1
MODELS ONLY' 
BATTERY FUSIBLE
LINK 
HORN
FUSIBLE LINK' 
TRANSISTOR 
FUSIBLE LINK'
Fig.
 4c— Circuitry - Voltage Regulator Assemblies (Corvette)
Engine compartment wiring harness incorporates sev-
eral fusible links. Each link is identified with its gage
size. A fusible link is a length of special wire (normally
four wire gages smaller than the circuit it is protecting)
used in wiring circuits that are not normally fused, such
as the ignition circuit. The same size wire with a hypalon
insulation must be used when replacing a fusible link.
The links are:
1.
 The pigtail lead at the battery positive cable (except
Corvette) is a 14 gage, brown fusible link protecting
the 10 gage battery charging circuit. This wire is an
integral part of the battery cable assembly and serv-
icing requires replacing the complete battery cable
assembly. On Corvette models this link is installed
as a molded splice at the solenoid "Bat" terminal
and servicing requires splicing in a new link.
2.
 A 16 gage black fusible link is located at the horn 
4. 
relay to protect all unfused wiring of 12 gage or
larger. It is installed as a molded splice and serv-
icing requires splicing in a new link.
The generator warning light and field circuitry (16
gage wire) is protected by a fusible link (20 gage
orange wire) used in the "battery feed to voltage
regulator #3 terminal" wire. The link is installed as
a molded splice in the generator and forward lamp
harness and is serviced by splicing in a new 20 gage
wire as required.
The ammeter circuit on all models is protected by
two orange, 20 gage wire fusible links installed as
molded splices in the circuit at the junction block or
the solenoid "Bat" terminal (Corvette only) and at
the horn relay. Each link is serviced by splicing in a
new 20 gage wire as required.
MAINTENANCE AND ADJUSTMENTS
At regular intervals, inspect the terminals for cor-
rosion an4 loose connections, and the wiring for frayed
insulation. Check mounting bolts for tightness. Check the
drive belt for alignment, proper tension and wear. Be-
cause of the higher inertia and load capacity of the rotor
used in A.C. generators, PROPER BELT TENSION is
more critical than on D.C. generators.
Since the Delcotron and its companion regulator are
designed for use on negative polarity systems only, the
following precautions must be observed. Failure to ob-
serve these precautions may result in serious damage to
the charging system.
1.
 When installing a battery, always make absolutely
sure the ground polarity of the battery, generator and
regulator is the same.
2.
 When connecting a booster battery, make certain to
connect the correct battery terminals together.
3.
 When connecting a charger to the battery, connect the
correct charger leads to the battery
 %
 terminals.
4.
 Never operate the generator on an uncontrolled open 
TO SOLENOID
BAT ACC RES. WIRE
Fig.
 5c—Typical Wiring Diagram Showing Lead Connections
CHEVROLET CHASSIS SERVICE MANUAL 

ELECTRICAL-BODY AND CHASSIS 12-2
FJg.
 1 - Fuse Panel Assembly
All power window and tailgate circuits require the igni-
tion switch to be "ON" to open or close the windows un-
like past model designs which were operated independ-
ently of the ignition switch.
The windshield wiper and washer switch is new in that
washer button in the center of the knob has been deleted 
and its function will be accomplished by pushing the knob.
A set screw is used to retain the knob to the shaft.
In addition to fuses, the wiring harness incorporates
fusible links to protect the wiring. Links are used rather
than a fuse in wiring circuits that are not normally fused,
such as the ignition circuit. Fusible links in the Chevro-
let wiring are four gauge sizes smaller than the cable it
is designed to protect. The links are marked on the
insulation with wire gauge size because of the heavy insu-
lation which makes the link appear a heavier gauge than it
actually is.
Engine compartment wiring harness incorporate sev-
eral fusible links. Each link is identified with its gauge
size.
 A fusible link is a length of special wire (normally
four wire gauges smaller than the circuit it is protecting)
used in wiring circuits that are not normally fused, such
as the ignition circuit. The same size wire with a spe-
cial hypalon insulation must be used when replacing a
fusible link.
The links are:
1.
 The pigtail lead at the battery positive cable (except
Corvette) is a 14 gauge, brown fusible link protecting
the 10 gange battery charging circuit. This wire is
an integral part of the battery cable assembly and
servicing requires replacing the complete battery
cable assembly. On Corvette models this link is
installed as a molded splice at the solenoid "Bat"
terminal and servicing requires splicing in a new
link.
2.
 A 16 gauge black fusible link is located at horn relay
to protect all unfused wiring of 12 gauge or larger.
It is a serviceable piece with an in-line connector
and is not integral with the wiring harness.
3.
 The generator warning light and field circuitry (16
gauge wire) is protected by a fusible link (20 gauge
orange wire) used in the "battery feed to voltage
regulator #3 terminal" wire. The link is installed
as a molded splice in the generator and forward lamp
harness and is serviced by splicing in a new 20 gauge
wire as required.
4.
 The ammeter circuit on all models is protected by
two orange, 20 gauge wire fusible links installed as
molded splices in the circuit at the junction block or
the solenoid "Bat" terminal (Corvette only) and at the
horn relay. Each link is serviced by splicing in a
new 20 gauge wire as required.
The wiring harnesses use a standarized. color code
common to all Chevrolet vehicles. Under the color code,
the color of the wire designates a particular circuit. The
harness title indicates the type of harness, single of mul-
tiple wire, and also describe the location of the harness.
The body harness is a flat, solid wire assembly and is
routed through the vehicle near the center of the body.
Composite wiring diagrams (figs. 104 thru 124) are in-
cluded at the end of this section.
MAINTENANCE AND ADJUSTMENTS
Maintenance of the lighting units and wiring system
consists of an occasional check to see that all wiring
connections are tight and clean, that the lighting units are
tightly mounted to provide good ground and that the head-
lamps are properly adjusted. Loose or corroded con-
nections may cause a discharged battery, difficult start-
ing, dim lights, and possible damage to generator and
regulator. Wire harnesses must be replaced if insulation
becomes burned, cracked, or deteriorated. Whenever it 
is necessary to splice a wire or repair one that is bro-
ken, always use solder to bond the splice. Always use
rosin flux solder on electrical connections. Use insulat-
ing tape to cover all splices or bare wires.
When replacing wires, it is important that the correct
size be used. Never replace a wire with one of a smaller
size.
Each harness and wire must be held securely in place
by clips or other holding devices to prevent chafing or
CHEVROLET CHASSIS SERVICE MANUAL 

ELECTRICAL-BODY AND CHASSIS 12-21
2.
 Remove ash tray, retainer attaching screws and
retainer.
3.
 Remove Air Conditioning distributor
 duct'
 retaining
screws and duct.
4.
 Remove heater and/or Air Conditioning control panel
assembly retaining screws and push panel assembly
from console.
NOTE:
 If interference between control panel
and radio is encountered, loosen radio retaining
nuts.
5. Remove radio control knobs, bezels and retaining
nuts.
6. Disconnect radio wiring harness and antenna lead-in.
7. Remove radio rear brace attaching screw and re-
move ra(Jio from vehicle.
8. Remove ignition switch bezel nut using Tool J-7607
and push switch rearward.
9. Disconnect cigarette wiring connector.
10.
 Remove cigarette lighter retainer and lighter as-
sembly from console.
11.
 To install, reverse removal procedure. 
Fig.
 35 - Cigarette Lighter — Chevelle
CHEVROLET INSTRUMENTS AND GAUGES
INDEX
Page
General Description 12-21
Service Operations 12-22
Instrument Cluster........................ 12-22
Instrument Cluster Lamps 12-22
Printed Circuit .
 * •
 12-22
Speedometer 12-22
Speedometer Cable 12-23
Fuel Gauge 12-23 
Page
Clock 12-24
Tachometer 12-24
Ammeter . . 12-24
Temperature Gauge 12-24
Oil Pressure Gauge 12-24
Oil Pressure Indicator 12-24
Generator Indicator 12-26
Temperature Indicator 12-26
GENERAL DESCRIPTION
The standard instrument cluster on all models contains
seven circular housings consisting of: a speedometer;
fuel gauge; oil pressure, generator and temperature indi-
cators; right and left directional signal indicators; brake
warning and high beam indicators; and includes a clock
on deluxe models. An optionally available instrument
cluster provides special instrumentation which includes
in addition to the speedometer and clock: a tachometer;
fuel, oil pressure, ammeter and engine temperature
gauges; which replace the standard fuel gauge and indi-
cator lights. The brake warning indicator is relocated
to the tachometer dial face and the high beam and direc-
tional indicators are positioned in the speedometer dial
face.
Instrument cluster removal is recommended before at-
tempting to service the printed circuit and gauges even
though some units may be accessible from behind the
cluster. Limited working space under the instrument
panel increases the possibility of electrical malfunctions
due to poor connections, and damaged or improperly in-
stalled printed circuit. The printed circuit is service-
able but not repairable and requires complete 
replacement.
The brake warning light serves a dual purpose. It
functions as an indicator when the parking brake is ap-
plied and also warns if a malfunction (loss of hydraulic
pressure) should occur in the brake system. The two
separate switches, which provide the signal to operate the
indicator, are located at the parking brake support and in
the hydraulic brake line at the master cylinder. Service
of the brake pressure, differential switch unit at the
master cylinder is described in Section 5 of this manual.
All indicator and cluster illumihating lamps may be
replaced without removing the cluster from the vehicle.
The bulbs are installed in plastic holders which lock into
the cluster housing and make contact with the printed
circuit. An instrument lamp is used to illuminate the
ignition switch. A special fibre optic lucite wiring
transmits light from the lamp to the switch.
Regular maintenance is not required on the instrument
cluster or its components other than maintaining clean,
tight electrical connections, replacing defective parts and
keeping the speedometer cable properly lubricated.
CHEVROLET CHASSIS SERVICE MANUAL 

ELECTRICAL-BODY AND CHASSIS 12-22
SERVICE OPERATIONS
INSTRUMENT CLUSTER
Removal and Installation (Figs. 36 thru 40)
I. Disconnect battery ground cable.
2:
 Remove four screws retaining instrument bezel to
top edge of instrument console. Disengage tabs on
bezel lower section from clips on instrument console
and remove bezel.
3.
 Protect mast jacket to prevent scratching when re-
moving cluster assembly.
4.
 Remove eight screws securing leading edges of in-
strument cluster to console and pull cluster forward
from console opening.
5. Reaching behind cluster disconnect speedometer ca-
ble,
 chassis harness connector, clock and speed
warning device connections (if so equipped) at rear of
cluster.
NOTE:
 On models- with gauge pack, disconnect
oil pressure line also.
6. When all disconnects are made, remove cluster as-
sembly from vehicle.
7. To install, position cluster assembly to console
opening and connect speedometer cable, chassis
harness connector and other electrical connections
as required.
8. Position cluster in console opening and install eight
retaining screws.
NOTE:
 Make sure ground strap between
cluster case and center right lower attachment
is properly installed.
9. Engage tabs on instrument bezel with clips on con-
sole and position bezel in console opening, then in-
stall four retaining screws.
10.
 Install speed warning device control attaching nut and
knob,
 if so equipped.
II.
 Connect battery ground cable and check operation of
cluster assembly.
Fig. 36 - Instrument Cluster Installation — Chevrolet 
Fig. 37 - Speed Warning Device
INSTRUMENT CLUSTER LAMP REPLACEMENT
(Figs.
 38 and 39)
1.
 Rotate socket counterclockwise to remove from rear
of cluster housing.
2.
 To remove bulb, if socket is black color, pull bulb
straight out. If socket is gray color, depress and
rotate bulb, then pull out.
3.
 Install replacement bulb in socket, pressing inward
to lock in place.
4.
 Insert socket into housing, with lugs entering notches
in case, and rotate clockwise to lock in place.
PRINTED CIRCUIT REPLACEMENT (Figs. 38 and 39)
1.
 Remove instrument cluster as previously described
in this section.
2.
 Remove all cluster illuminating and indicator lights
from cluster housing.
3.
 Remove fuel gauge and clock terminal nuts securing
printed circuit to housing.
4.
 Remove four hex head screws retaining printed cir-
cuit to the cluster housing and remove the printed
circuit. . .
5. To install, reverse removal procedure.
CAUTION:. The retaining screws and terminal
nuts are part of the grounding circuit and must
be installed to provide the proper ground con-
nections for the printed circuit.
SPEEDOMETER
 REPLACEMENT
1.
 Remove instrument cluster as previously described
in this section.
2.
 Remove screws retaining rear cover to the cluster
assembly. Bend ground strap away from cover and
remove cover.
CHEVROLET CHASSIS SERVICE MANUAL 

ELECTRICAL-BODY
 AND
 CHASSIS
 12-26
•
 Low oil
 pressure
• High engine temperature
• Defective wiring
 or
 switch
connector from sender
in block above starter
 on
and
 at
 left front
 of
 distributor
 on V-8
Sending Unit Replacement
1.
 Disconnect wiring harness
unit terminal (located
L-6 engines
engines).
2.
 Remove sender unit using Tool J-21757
 or 12
 point
socket, replace with
 new
 unit
 and
 check operation.
GENERATOR INDICATOR
1.
 Ignition
 on,
 Engine
 not
 Running
 and
 Telltale Light
Off.
• Indicator bulb burned out, replace bulb.
• Open circuit
 or
 loose connection
 in the
 telltale
light circuit.
2.
 telltale Light Stays
 on
 after Engine
 is
 Started. 
If indicator light does
 not go out at
 engine idle
speed, refer
 to
 Charging Systems under Engine
Electrical, Section
 6Y.
TEMPERATURE (COOLING SYSTEM) INDICATOR
The temperature indicator circuit consists
 of two re-
motely located units, indicator gauge
 and
 engine sender
unit.
 The
 indicator gauge, located
 in the
 instrument
panel, consists
 of a
 red light which will indicate
 an
 over-
heated engine condition.
Engine Sender Unit Replacement
1.
 Drain engine cooling system
 to a
 level below unit.
2.
 Remove sender unit (located
 in the
 inlet manifold
near water pump housing
 on V-8
 engines and
 in the
cylinder head near
 an
 exhaust port
 oh L-6
 engines)
and replace with new unit.
3.
 Refill cooling system
 and
 check operation
 of
 unit.
CHEVELLE INSTRUMENTS AND GAUGES
INDEX
Page
General Description
 * *
 i2-26
Service Operations
 12-26
Instrument Panel
 12-26
Instrument Cluster.
 12-26
Fuel Gauge and/or Ammeter
 12-27
Clock,
 i 12-27
Speedometer
 12-27 
Page
Speedometer Cable
 .
 . 12-27
Temperature Gauge
 12-29
Oil Pressure Gauge
 12-29
Indicator Lights.
 . 12-29
Oil Pressure Indicator
 12-29
Generator Indicator
 . . 12-29
• Temperature Indicator
 12-29
GENERAL DESCRIPTION
The Chevelle instrument cluster assembly consists
 of:
a speedometer;
 a
 fuel gauge;
 a
 generator,
 an
 engine
 tem-
perature and an
 oil
 pressure indicator lamp, and includes
a clock
 on
 deluxe models.
 On
 super sport models,
 am-
meter, coolant temperature
 and oil
 pressure gauges
 re-
place
 the
 appropriate indicator lights. Except
 for the
speedometer,
 all of the
 indicator lamps, instruments
 and
gauges
 of
 these clusters may
 be
 serviced without remov-
ing
 the
 instrument cluster assembly from
 the
 vehicle.
In addition
 to the
 instrument indicator lamps,
 a
 brake
warning lamp
 is
 included
 in the
 cluster
 as
 standard
equipment.
 The
 indicator
 is
 connected
 to the
 parking 
brake
 and
 brake pressure differential switches
 and
serves
 a
 dual function.
 It
 lights when the parking brake
is applied
 and
 also when
 the
 brake pedal
 is
 applied,
 if a
malfunction should occur
 in the
 brake system
 due to a
loss
 of
 hydraulic pressure. Servicing
 of the
 hydraulic
pressure differential switch
 is
 covered
 in
 Section
 5 of
this manual.
Regular maintenance
 is not
 required on the instrument
cjLuster
 or its
 components other than maintaining dean
and tight electrical connections, replacing defective parts
and keeping
 the
 speedometer cable properly lubricated.
SERVICE OPERATIONS
INSTRUMENT PANEL ASSEMBLY
INSTRUMENT CLUSTER (Figs.
 41
 thru
 44)
Removal
1.
 Disconnect battery ground cable.
2.
 Remove steering coupling bolt and disconnect steer-
ing shaft from coupling.
3.
 Loosen mast jacket lower clamp.
4.
 Remove
 air
 conditioning center distributor duct
 (if
so equipped).
5. Remove radio rear support bracket screw.
6. Remove mast jacket upper support clamp and retain-
ing bolts from lower support (refer
 to
 Section
 9,
Steering). 
CAUTION: Cover mast jacket
 and
 parl
brake handle with
 a
 suitable material
 to
 prevc
scratching.
7. 
Disconnect speedometer cable
 at
 rear
 of
 cluster
housing
 and
 speed warning control knob
 at
 panel
 (if
so equipped).
8. Remove instrument panel retaining screws (nine
upper and five lower).
 .
9. Working under the console remove four lower retain-
ing screws from instrument cluster housing.
10.
 Pull instrument panel assembly from console and
 lay
forward on mast jacket.
11.
 Disconnect wiring harness, cluster lamps and wiring
CHEVROLET CHASSIS SERVICE MANUAL 

ELECTRICAL-BODY AND CHASSIS 12-29
Fig.
 43b - Speed Warning Device
TEMPERATURE AND/OR OIL PRESSURE
GAUGE
1.
 Disconnect battery ground cable.
2.
 Remove ash tray and ash tray retainer.
3.
 Disconnect A/C hose from the distributor duct.
4.
 Disconnect wiring connectors and lamp bulbs from
rear of gauge.
5. Disconnect oil pressure pipe fitting from rear of oil
pressure gauge.
6. Remove (3) screws retaining gauge assembly to
cluster cover and disengage unit from cover.
7. Remove (4) retaining nuts and remove gauge from
template.
8. To install, reverse removal procedure.
INDICATOR LIGHT REPLACEMENT
To replace any indicator or cluster bulb, unsnap the
proper socket from rear of instrument cluster, remove
and replace bulb, and reinsert unit into rear of cluster
housing. 
OIL PRESSURE INDICATOR
If the light does not come on when the ignition switch is
turned on, or if the light comes on and remains on after
the engine is started, one or more the following condi-
tions is indicated:
• Low oil pressure
• Defective wiring or switch
• High engine temperature
Switch Replacement
1.
 Disconnect wiring harness connector from sender
unit terminal (located in block above starter on L-6
engines and at left front of distributor on V-8
engines).
2.
 Remove sender unit using Tool J-21757, replace with
new unit, and check operation.
GENERATOR INDICATOR
Ignition on, Engine not Running and
Telltale Light Off
1.
 Indicator bulb burned out, replace bulb.
2.
 Open circuit or loose connection in the telltale light
circuit.
Telltale Light Stays on after Engine is Started
If indicator light does not go out at engine idle speed,
refer to' Charging Systems under Engine Electrical,
Section 6Y.
TEMPERATURE
 (COOLING
 SYSTEM)
 INDICATOR
The temperature indicator circuit, consists of two re-
motely located units, indicator gauge and engine sender
unit. The indicator gauge on all models uses a single
red light to indicate an overheated engine condition.
Engine Sender Unit Replacement
1.
 Drain engine cooling system to a level below unit.
2.
 Remove sender unit (located in the inlet manifold
near water pump housing on V-8 engines and in the
cylinder head near an exhaust port on L-6 engines)
and replace with new unit.
3.
 Refill cooling system and check operation of unit.
CHEVROLET CHASSIS SERVICE MANUAL 

ELECTRICAL-BODY
 AND
 CHASSIS
 12-31
CHEVY II INSTRUMENTS AND GAUGES
INDEX
Page 
Page
General Description -.....
 12-31
Service Operations.
 12-31
Instrument Panel
 . 12-31
Instrument Cluster
 12-31
Fuel Gauge
 12-32
12-32
Clock, 
Speedometer
 12-34
Speedometer Catte
 12-34
Indicator Lights
 12-34
Oil Pressure Indicator
 12-34
Generator Indicator
 12-34
Temperature Indicator
 12-34
GENERAL DESCRIPTION
The Chevy
 n
 instrument cluster assembly consists
 of:
a speedometer;
 a
 fuel gauge;
 a
 generator, temperature
and
 oil
 pressure indicator lamps, and includes
 a
 clock
 on
deluxe models. Except
 for the
 speedometer,
 all of the
cluster lamps, instruments and gauges
 of
 the cluster
 may
be serviced without removing
 the
 instrument cluster
 as-
sembly from
 the
 console.
In addition
 to the
 instrument indicator lamps,
 a
 brake
warning lamp
 is
 included
 in the
 cluster
 as
 standard
equipment.
 The
 indicator
 is
 connected
 to
 thfc parking
brake and brake pressure differential switches andserves 
a dual function.
 It
 lights when
 the
 parking brake
 is ap-
plied
 and
 also when
 the
 brake pedal
 is
 applied,
 if a mal-
function should occur
 in the
 brake system
 due to a
 loss
 of
hydraulic pressure. Servicing
 of the
 hydraulic pressure
differential switch
 is
 covered
 in
 Section
 5 of
 this manaul.
Regular maintenance
 is not
 required on
 the
 instrument
cluster
 or its
 components other than r^Mfitftl^i^g clean
and tight electrical connections, replacing defective parts
and keeping
 the
 speedometer cable properly lubricated.
SERVICE OPERATIONS
INSTRUMENT PANEL
INSTRUMENT CLUSTER
Removal
 and
 Installation {Figs.
 45
 thru
 48)
1.
 Disconnect battery ground cable.
2.
 Remove mast jacket upper support clamp (refer
 to
Steering, Section
 9, for
 complete procedure
 on low-
ering jacket) and lower steering column.
NOTE:
 Apply protective material
 to the
 mast
jacket
 to
 prevent damage
 to the
 painted surfaces. 
3.
 Disconnect retaining collar securing speedometer
cable
 to
 speedometer head.
4.
 Remove screws retaining cluster
 to
 console.
5. Pull cluster forward
 of
 console opening and discon-
nect
 all
 wiring
 and
 lamp connections. Remove
cluster from vehicle.
CAUTION:
 Do not
 pull cluster outward further
than slack
 in
 wiring harness will allow, other-
Fig.
 45-
 Instrument Cluster Installation
 —
 Chevy
 II
Fig.
 46 -
 Speed Warning Device
CHEVtOtET CHASSIS SERVICE MANUAL 

ELECTRICAL-BODY
 AND
 CHASSIS
 12-36
CAMARO INSTRUMENTS AND GAUGES
INDEX
Page
General Description
 12-36
Service Operations
 12-36
Instrument Cluster
 . . . 12-36
Instrument Lamps
 12-36
Printed Circuit
 12-36
Fuel Gauge
 12-37
Tachometer
 . . 12-37
Seat Separator Instrument Console
 12-37 
Page
Fuel Gauge
 12-37
Ammeter
 12-37
Temperature Gauge
 12-37
Oil Pressure Gauge
 . 12-37
Fuel Warning Unit
 12-37
Clock.
 ... 12-37
Oil Pressure Indicator
 12-37
Generator Indicator
 12-38
Temperature Indicator
 12-38
GENERAL DESCRIPTION
The standard Camaro instrument cluster assembly con-
sists
 of two
 circular units which house
 the
 speedometer
and fuel gauge assemblies.
 The oil
 pressure, left-hand
directional
 and
 brake warning indicators
 are
 located
 in
the face
 of the
 speedometer bezel while generator,
 tem-
perature
 and
 right-hand directional indicators are grouped
with
 the
 fuel gauge unit.
 The
 high beam indicator
 is
located between
 the
 cluster bezels.
A special instrumentation package
 is
 available with
 the
eight-cylinder engine
 and
 center floor console combina-
tion.
 The
 special cluster includes:
 a
 clock; coolant
temperature,
 oil
 pressure, fuel
 and
 ammeter gauges,
mounted forward
 on the
 seat separator console;
 a ta-
chometer
 in the
 right circular housing
 of the
 dash
 in-
strument cluster; and
 a low
 fuel level indicator replacing
the
 oil
 pressure indicator lamp
 in the
 instrument cluster.
The instruments
 and
 gauges,
 may be
 serviced only
after
 the
 instrument cluster
 is
 removed from
 the
 vehicle.
Indicator
 and
 cluster lamps except
 for the
 high beam
indicator
 may be
 replaced without removing
 the
 cluster
assembly. Partial cluster removal
 is
 necessary when
replacing
 the
 high beam indicator due
 to its
 proximity
 to 
the upper brace
 rod
 anchor plate.
 The
 bulbs
 are in-
stalled
 in
 plastic sockets which lock into
 the
 cluster
housing and make contact with
 the
 printed circuit.
A
 low
 level fuel warning system
 is a
 special feature
available with
 the
 floor console gauge pack. This
 sys-
tem includes
 an
 indicator lamp
 in the
 dash cluster and
 a
semi-conductor unit senses
 the
 change
 in
 electrical
 re-
sistance
 of the
 fuel system circuitry
 as
 variations
 in
fuel level occur.
 The
 sensing device
 is
 replaced
 as a
unit
 if
 found defective.
The brake warning light serves
 a
 dual purpose.
 It
functions
 as an
 indicator when
 the
 parking brake
 is ap-
plied
 and
 also
 if
 there
 is a
 malfunction (loss
 of
 hydraulic
pressure)
 in the
 brake system. Switches which provide
the signal
 to
 operate
 the
 light
 are
 located
 at the
 parking
brake assembly
 and at the
 brake master cylinder
 in the
hydraulic lines. Service
 of the
 brake pressure differ-
ential switch unit
 is
 covered
 in
 Section
 5 of
 this manual.
Regular maintenance
 is not
 required on
 the
 instrument
cluster
 or its
 components other than maintaining clean,
tight electrical connections, replacing defective parts
and keeping
 the
 speedometer properly lubricated.
SERVICE OPERATIONS
INSTRUMENT CLUSTER (Figs.
 50
 thru
 53)
Removal
 and
 Installation
1.
 Disconnect battery ground cable.
2.
 Remove mast jacket lower support screws
 at toe
 pan.
3.
 Remove mast jacket upper support bolts
 and
 allow
steering wheel
 to
 rest
 on
 seat cushion.
CAUTION: Both supports must
 be
 detached
 to
prevent distortion
 of
 mast jacket.
4.
 Remove cluster attaching screws from face
 of
 panel
and partially remove assembly from console opening.
5. Reaching behind cluster assembly, disconnect speed-
ometer cable, speed warning device
 (if so
 equipped
 -
Fig.
 51) and
 chassis harness connector
 at
 rear
 of
panel.
6. Remove assembly from console opening to
 a
 suitable
bench area
 for
 required service operations.
7.
 To
 install, reverse removal procedure.
INSTRUMENT CLUSTER LAMP REPLACEMENT
1.
 Turn bulb holder counterclockwise
 and
 pull
 out to
remove from
 the
 cluster housing. 
2.
 Pull bulb straight out
 to
 remove from socket.
3.
 Press replacement bulb inward
 to
 lock
 in
 socket.
4.
 Insert lamp assembly into housing, with lugs
 on
holder entering notches
 in
 housing,
 and
 turn clock-
wise
 to
 lock
 in
 place.
PRINTED CIRCUIT REPLACEMENT
1.
 Remove instrument cluster
 as
 previously described
in this section.
2.
 Remove
 all
 cluster illuminating and indicator lamps
from housing.
3.
 Remove fuel gauge terminal nuts
 or
 tachometer
 re-
taining nuts securing printed circuit
 to
 housing.
4.
 Remove four
 hex
 head screws retaining printed
 cir-
cuit
 to the
 cluster housing
 and
 remove circuit from
housing.
5.
 To
 install, reverse removal procedure.
CAUTION:
 The
 retaining screws
 are
 part
 of
the grounding circuit
 and
 must
 be
 installed
 to
provide proper connections
 for the
 printed
 eir-
cuit.
CHEVROLET CHASSIS SERVICE MANUAL