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 12-8
is inserted through radiator support opening.
Remove two screws retaining lamp assembly to
lower sheet metal.
Remove three screws retaining lamp assembly to
lender.
To replace lamp assembly, reverse removal proce-
dure and check operation of the unit.
is aligned with flat on pivot shaft. Install stop lock
bolt and torque bolt to 45-60 in, lbs. Make sure that
side-to-side panel alignment is not changed when in-
stalling and tightening the stop.
CAUTION: Do not exceed specified torque
when tightening stop lock bolt.
HEADLAMP PANEL REPLACEMENT-CORVETTE
Refer to Figure 13 for Panel Mounting details.
1.
Remove engine compartment hood as outlined in
Section 1.
2.
Actuate headlamp panel to the open position.
NOTE:
In the event headlamp motor is inop-
erative, manual positioning of the panel can be
accomplished by turning the knurled knob at in-
board end of motor. As an assist in manual
operation of panel, apply light hand pressure to
panel in desired direction of rotation.
3.
Remove positive lead from battery terminal.
4.
Remove headlamp bezel retaining screws and bezel.
5. Remove the sealed beam housing unit as an assem-
bly - disconnect sealed beam leads at harness con-
nector and remove connector from sealed beam
leads;
remove the housing-to-panel retaining screws
and remove housing unit and wiring from panel.
6. Remove motor from panel pivot shaft - see motor
removal procedure. Then remove the panel stop
from panel inboard pivot shaft, and disconnect switch
lead wires from panel, support-mounted motor
switch.
7. Remove the panel retaining bolt access hole plugs
from inside the panel then rotate panel as required
and remove the retaining bolts and slide supports
from ends of panel pivot shaft. Remove bearing, felt
seal, retainer and washer from inboard pivot shaft.
8. Remove panel from its location by alternately disen-
gaging pivots from their retaining slots and with-
drawing unit forward through opening in body (fig.
14).
9. Loosen alien screw in spacer and disassemble parts
from the panel outboard pivot shaft.
10.
Install washer, retainer, felt seal, bearing and
spacer, in that order, to panel outboard pivot shaft.
Do not tighten spacer on shaft at this time.
11.
Position panel in body opening and index panel pivot
shafts in retaining slots; then loosely install support
retaining bolts.
12.
Install washer, retainer, felt seal, bearing and sup-
port, in that order, to panel inboard pivot shaft, and
loosely install support retaining bolts. -
13.
Check side-to-side alignment of panel, making sure
that there is no panel-to-body contact; position
spacer snugly against bearing; then tighten spacer
seat screw to 30-50 in. lbs.
14.
Install stop on panel inboard shaft so that it rests
against bearing, being sure that index mark on stop
15.
Check and align panel to body as follows:
a. Tighten panel pivot support bolts snugly but still
allowing panel to" be moved by applying hand
pressure.
b.
Position panel to the closed position and align
with body so that all surfaces are flush.
c. With the panel in the closed position the outboard
access hole is aligned with the forward bolt head.
Tighten this bolt with the panel in the closed
position - access to bolt head can be obtained by
working through opening between the hood and
body.
d. Rotate panel to obtain access to each bolt head
and torque bolts to 100-140 in. lbs.
e. Connect switch lead wires to support-mounted
limit switch.
16.
Install seaLed beam housing unit and at the same time
position sealed beam lead wires through panel out-
board pivot shaft. Install housing unit retaining
screws and install lead wires in connector, making
sure to match colors between harness and connector.
17.
Install motor assembly - see motor replacement
procedure.
18.
Connect positive lead to battery terminal.
19.
Adjust headlamp panel as outlined under "Headlamp
Panel Travel Adjustment".
20.
Adjust headlamp aiming as outlined under "Headlamp
Adjustment".
21.
Install headlamp bezel and engine compartment
hood - refer to Section 1 for hood installation.
Fig.
14
- Headlamp Panel Removal (Corvette)
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 12-34
5. To replace, reverse the removal procedure.
SPEEDOMETER REPLACEMENT
1.
Remove instrument cluster as previously described
in this section.
2.
Remove clock set shaft knob.
3.
Remove eight screws securing cluster housing to
bezel trim panel. Separate parts carefully observing
stack up of parts.
4.
Remove two screws securing speedometer head to
rear of cluster housing.
NOTE:
Servicing of the speedometer head
should be performed by an authorized AC Speed-
ometer Service Station.
5. To install, reverse the removal procedure..
SPEEDOMETER CABLE
Replacement or Lubricatibn
1.
Disconnect the speedometer cable from the speed-
ometer head. Remove the old cable by pulling it out
from speedometer end of conduit.
NOTE:
If old cable is broken it may be neces-
sary to remove lower piece from transmission
end of conduit.
2.
Lubricate the lower 3/4 of cable with speedometer
cable lubricant and push the cable into the conduit.
Connect the upper end to the speedometer head and
road test vehicle for proper speedometer operation.
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 of the following
conditions is indicated:
• Low oil pressure
• High engine temperature
• Defective wiring or switch
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, replace with new unit, and
; check operation.
GENERATOR INDICATOR
1.
Ignition on, engine not running and telltale light off.
a. Indicator bulb burned out, replace bulb.
b.
Open circuit or loose connection in the telltale
light circuit.
2.
Telltale light stays on after engine is started.
a. 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.
CORVETTE INSTRUMENTS AND GAUGES
INDEX
Page
General Description ., 12-34
Service Operations . 12-35
Instrument Cluster ., 12-35
Fuel Gauge 12-35
Speedometer/Tachometer Service. 12-35
Temperature Gauge 12-35
Ammeter/Oil Pressure Gauges 12-35
GENERAL DESCRIPTION
All Corvette instruments and gauges are conveniently
located in the dash-mounted cluster. The entire cluster
is removable to permit servicing of the various instru-
ments and gauges. The indicator and cluster illuminating
bulbs may be replaced without removing the cluster from
the panel.
Regular maintenance is not required on the instrument
cluster or its components other than maintaining clean
and keeping the speedometer and tachometer cables
properly lubricated.
CHEVROLET CHASSIS SERVICE MANUAL
ELECTRICAL-BODY AND CHASSIS 12-35
SERVICE OPERATIONS
INSTRUMENT CLUSTER
REMOVAL AND INSTALLATION (Fig. 49)
1.
Remove mast jacket assembly. Refer to Section 9
for removal procedures.
2.
Disconnect tachometer drive cable at distributor.
3.
Disconnect the headlamp panel control switch from
instrument cluster.
4.
Remove lighting switch as outlined in this section.
10 10-A 1112 13
14
15 16 17 18 19
Fig.
49- Instrument Cluster Connections
1.
Cluster Illuminating
Bulbs
2.
Direction Signal Indicator
Bulb L.H.
3. Direction Signal Indicator
BulbR.H.
4.
Headlamp Actuating Motor
Indicator
5. Headlamp Hi Beam
Indicator
6. Parking Brake Alarm
Indicator
7. Ground Lead Attaching
Point
8. Temperature Indicator
"1"
Terminal
9.
10.
10A.
11.
12.
13.
14.
]5.
16.
17.
18.
19.
20.
21.
Temperature Indicator "S"
Terminal
Ignition Switch Receptacle
ignition Switch Illuminating
Bulb
Oil Pressure Indicator
Tachometer
Lighter Receptacle
Trip Odometer
Wiper Switch Receptacle
Speedometer
Ammeter "Gen" Terminal
Ammeter "Battery" Terminal
Lighting Switch Receptacle
Fuel Gauge
"1"
Terminal
Fuel Gauge "S" Terminal
5. Remove the ignition switch. Refer to Section 6Y
for removal procedure. Then disconnect ignition
switch lamp support at instrument panel.
6. Disconnect oil pressure line at oil pressure gauge
then remove the lead wires from ammeter, wiper
switch and cigarette lighter. Disconnect trip odom-
eter at mast jacket support.
7. Remove the instrument cluster-to-dash retaining
screws and pull cluster assembly slightly forward
to obtain clearance for removal of speedometer
cable, tachometer cable, cluster ground wire, fuel
gauge lead wires and remaining indicator and cluster
illuminating lamps.
8. To install cluster in dash panel, reverse removal
procedure.
FUEL GAUGE
The gasoline fuel gauge circuit consists of an electri-
cal indicator in the instrument cluster and a float-
controlled rheostat in the fuel tank.
Since the fuel gauge consists of two remotely located
units and connecting wires, it is sometimes difficult to
determine which unit is at fault when the gauge fails to
operate properly. Cluster removal is necessary to re-
place the fuel gauge.
NOTE:
Be sure to check gas gauge fuse in fuse
panel before attempting to trouble shoot for
inoperative gauge or tank sending unit.
SPEEDOMETER AND/OR TACHOMETER
Removal and Installation
Cluster must be removed from vehicle to service
speedometer head assembly (see Cluster Removal pro-
cedure)
.
With cluster removed from vehicle:
1.
Remove five screws securing cluster back panel to
cluster assembly; separate the parts carefully.
CAUTION: Care must be used to avoid marring
instrument cluster face.
2.
Remove two screws securing speedometer or ta-
chometer head to cluster back panel; carefully re-
move speedometer or tachometer head.
NOTE:
Servicing of speedometer or tachom-
eter head should be performed by an authorized
AC service station.
3.
Reverse above procedure to install speedometer.
Cable Replacement or Lubrication
1.
Disconnect the. cable from the speedometer or ta-
chometer head. Remove the old cable by pulling it
out from speedometer end of conduit.
NOTE:
If old cable is broken it may be nec-
essary to remove lower piece from transmission
or distributor end of conduit as applicable.
2.
Lubricate the lower 3/4 of cable with
AC
speedom-
eter cable lubricant and push the cable into the con-
duit. Connect the upper end to the speedometer or
tachometer head and road test vehicle for proper
operation.
TEMPERATURE GAUGE
The temperature indicator requires very little service
other than testing for malfunctioning and replacing de-
fective units. Cluster must be removed to service tem-
perature gauge.
Do not attempt to repair either the engine unit or the
gauge. When installing new engine unit, do not use
thread compound on unit threads, as this will increase
electrical resistance of unit and cause faulty reading
on gauge.
AMMETER OR OIL PRESSURE GAUGE
The ammeter or oil pressure gauge requires very
little attention other than keeping ammeter terminals
clean and tight. If the oil pressure control line should
become restricted it should be blown out or replaced.
Cluster must be removed to service these gauges.
HftVKI MANUAL
ELECTRICAL-BODY AND CHASSIS 12-38
Fig.
52 - Instrument Cluster Lighting
1
• Cluster Lamp
2.
* High Beam Indicator
3. Oil Pressure Indicator
4.
L.H. Directional Indicator
5. Generator indicator
6. R.H. Directional indicator
7. Temperature Indicator
8. Printed Circuit
9. Chassis Harness Connector
10,
Brake Warning Indicator
2.
Remove sender unit.
3.
Replace with new unit and check operation.
GENERATOR INDICATOR
1.
Ignition on, engine not running and indicator light off:
•Indicator bulb is burned out, replace bulb.
•Open circuit or loose connection in the indicator
light circuit.
2.
Indicator light stays on after engine is started:
•Ti indicator light does not go out at engine idle
speed, refer to Charging System Tests in Section
6Y, Engine Electrical.
TEMPERATURE (COOLING SYSTEM) INDICATOR
The temperature indicator circuit consists of two re-
motely located units, indicator lamp and sending unit.
The "indicator lamp, located in the instrument cluster
CHfVROtEr CHASM SfXVICf
ELECTRICAL-BODY AND CHASSIS 12-40
Fig.
54 - Seat Separator Instrument Console
consists of a single 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 cylinder head near
an exhaust port on L-6 engines and in the inlet mani-
fold near water pump housing on V-8 engines).
3.
Replace unit, refill cooling system and check opera-
tion of unit.
DIRECTIONAL SIGNAL
Directional signal assemblies provide as standard pro-
duction equipment a lane changing feature and hazard
warning system on all model applications. Two different
design switches are used as shown in Figure 55. Major
difference between the two units is that one type has can-
celling and detent springs which are serviceable, other-
wise both units are not repairable and must be replaced
as an assembly in service.
Due to the integral design relationship of the signal
switch and the energy absorbing steering column, refer-
ence should be made to Steering, Section 9 of this manual
whenever any service operations are performed on the
steering column. The directional signal switch replace-
ment procedures covered in this section are intended to
supplement the detail service operations outlined in Sec-
tion 9.
Special note should be taken of the fact that different
signal flasher units are used in Chevrolet models depend-
ent on the number of lamps to be operated. The hazard
warning unit, even though an integral component of the
directional switch assembly, requires the installation of
an additional flasher unit in the fuse panel capable of op-
CHEVROtET CHASSIS SERVICE MANUAL