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15-14
PART
15-4
INSTRUMENTS
Sec:tion
Pare
1.
Description and Operation
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15-14
Gauges
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15-14
Constant Voltage
Regulator
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15-14
Fuel
Gauge. .
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15-14
Temperature
Gauge . . .
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15-15
Charge
Indicator
Light
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15-15
Oil Pressure Indicator Light
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15-15
Turn
Indicator
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15-15
Speedometer . . .
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15-15
Brake Warning Lamp
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15-15
2. In-Car
Adjustments and Repairs
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15-15
Windshield Wiper Blade Adjustment
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15-15
3.
Removal and Installation
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15-15
Instrument
Cluster
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15-15
Fuel, Temperature Gauges
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15-16
Printed Instrument Circuit
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15-16
Fuel Sending Unit
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15-17
Section
Temperature Sending Unit
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Oil Pressure Switch
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Turn Indicator Switch
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Turn Indicator Flasher ................... .
Speedometc!r and Tachometer
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Speedometer Cable
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Windshield Wiper Motor
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Wiper Pivot Shaft and Link
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Pare
15-17
15-17
15-17
15-17
15-16
15-16
15-17
15-17
4. Major Repair Operations
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15-18
Disassembly-Permanent Magnet Type Two-
Speed Electric Wiper Motor
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15-19
Inspecting and Testing Disassembled Motor .... 15-19
Testing and Assembled Motor
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15-20
NOTE:
If
the instruments require servicing while the assembly is removed from the instrument panel,
the cluster
case must be earthed to the vehicle body. Failure to observe this precaution will cause immediate
damage
to
the fuel and temperature gauges as soon as any power is applied to the electrical circuits.
D
DESCRIPTION AND OPERATION
All of the
instruments
are electri-
cally operated
except the speedome-
ter.
Brightness of the
instrument
pan-
el
lights is
controlled by a rheostat
adjacent to the
lighting switch.
GAUGES
The
instrument
cluster includes
a
fuel gauge,
temperature gauge,
charge
indicator
light, oil pressure
indicator
light, speedometer, high
beam
indicator
light, a left- and
right-hand turn signal
indicator light,
brake
warning
light, and
stop
lamp
and brake warning light.
CONSTANT VOLTAGE
REGULATOR
The constant voltage regulator
(Fig.
17)
used
with the
fuel,
tempera-
ture, and oil gauges maintains an
average value of S.O volts at the
gauge terminals.
The regulator operates by means
of a bimetallic arm and a heating
coil. When the ignition switch is
turned on, the heating coil (Fig. 17).
heats the bimetallic arm causing it
to bend and break the contacts, dis-
connecting the voltage supply from
the heating coil. The bimetallic arm
then cools and brings the contacts
together again. The making and
breaking of the contacts, causes a
pulsating voltage, with an effective
average value of S.O volts to be sup-
plied to the gauges. Although these
pulsations are quite rapid, there is
in each gauge a bimetallic arm which
changes temperature quite slowly,
and this assures steady average read-
ings.
As the pulsating voltage would
normally cause radio interference, a
radio interference suppression choke
is connected in series with the con-
stant voltage regulator supply wire.
FUEL GAUGE
The fuel gauge consists of a send-
ing unit, located on the fuel tank, and
a remote register unit (fuel gauge)
mounted in the instrument cluster.
The
remote
register unit pointer is
controlled by a bimetallic arm and
heating coil. The sending unit is a
TEMPERATURE GAUGE
UNIT
FIG. 17- Gauge Voltage Regulator
and Temperature Gauge - Typical.
rheostat that varies its resistance de-
pending on the amount of fuel in the
tank. The rheostat is operated by a
float control. As the fuel level rises or
falls the float control arm moved by
the float, varies the resistance.
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