1957 FIAT 500 diagram

4
53 2 1
7
6
FIG 11 :6 Regulator assembly GN 1.12.16
Key to Fig 11:6 1 Voltage regulator adjusting spring
2 Current regulator adjusting spring 3 Cutout adjusting
spring 4 Voltage regulator adjustment arm 5 Current
regulator adjustment arm 6 Cutout adjustment blade spring
7 Soldering of cutout shunt and series winding
FIG 11:7 Wiring diagram for checking the cutout
closing voltage
Key to Fig 1 1 : 7 GR Regulator GN 1.12.16 G Generator
FIAT DSV 90.12.1 6.3 S V Voltmeter, 20 V scale (0.5%
accuracy) L 12 V, 3 to 5 W bulb
FIG 11:8 Wiring diagram for checking the reverse
current of cutout
Key to Fig 11:8 GR Regulator GN 1.1 2.1 6 G Generator
FIAT DSV 90.1 2.1 6.3 S B Battery, 50 Ah, fully charged
A Ammeter, asymmetrical scale 10-0-15 A V Voltmeter,
20 V scale (0.5% accuracy)
116spring 13. Should any defect be found then the pinion
assembly must be renewed as one complete unit. After
examining to ensure that there are no defects thoroughly
clean using petrol.
Reassembling and refitting the starter:
In both cases this is a simple reversal of the dismantling
procedure. Grease t h e drive splines and the engagement
lever groove in the sleeve.
11:5 The control box:
Description:
The generator regulator fitted to the new 500 model
consists of three separate
units; voltage regulator,
current regulator, cut-out relay (see FIG 11 :6).
The voltage regulator and current regulator relays
comprise a U-shaped body one of whose arms is bent
to form a flange, whilst the other adjustment arm pro-
vides a stop for the hinge spring. The U-shaped body is
secured to the frame by the core threaded shank and
carries, on the flanged end, an armature supported by a
hinge spring which comprises a steel leaf and bi-metal
leaf overimposed in the current regulator and bi-metal
leaf in the voltage regulator. The armature carries the
movable contact.
Fixed contacts of both voltage and current regulators
are mounted on t w o blade springs which are secured to a
single bracket rivetted to the U-shaped adjustment arm.
The design of the t w o fixed contacts carrier blade springs
is such as to permit the adjustment of the contact
position by suitably bending the blade springs. The cut-
out is similar in design to the other two relays as shown
in FIG 11:6. Again the hinge spring is bi-metallic as in
the voltage regulator.
All the armatures are provided w i t h blade springs, so
that the tension may be adjusted to the required setting
value. This adjustment is obtained by bending the
adjustment arms.
The voltage regulator coil comprises a fine wire wind-
ing w i t h a great number of turns, shunt connected to the
generator.
The cut-out coil comprises a fine wire winding with a
great number of turns shunt connected to the generator,
and of a winding comprising a few turns of heavy gauge
wire, which is connected in series w i t h the generator
charge circuit (cut-out series winding).
The current regulator coil comprises a few turns of
heavy gauge wire which is series connected with the
generator charge circuit.
The generator regulator base has three terminals to
which the various cables are connected.
No. 51 — connection to generator positive terminal.
No. 67 — connection to generator field winding.
No. 30 — connection to electrical accessories.
The regulator cover is secured to the base w i t h a
rubber gasket placed in between which seals the unit
against the ingress of moisture or dust.
A regulation resistor is fitted under the base and is
secured to the voltage regulator and current regulator
relay core threaded shanks.

Checking cut-out:
1 Closing voltage:
This test should be carried out at a temperature of
25°±10°C and the regulator should be connected to a
generator test bed as shown in FIG 11:7. The unit should
be operated under no load conditions for between 15 -
18 minutes with the cover installed and w i t h a voltage of
between 16.5 volts for an initial operating temperature of
15-20°C or 15 volts for an initial operating temperature
of 20-35°C. This will enable thermal stabilization of the
unit to be obtained so that the temperature of both the
cut-out shunt windings and the bymetallic springs
increase due to the heat developed by the windings and
reaches the normal operating setting.
Once thermal stabilization has been obtained the
generator should be restarted and the speed gradually
increased so that immediately the test lamp starts to
glow the voltmeter reading may be taken. This will be
the value of the cut-out contact closing voltage.
2 Reverse current:
This check should be carried out at a temperature range
of between 25°±10°C and it is recommended that it is
performed as soon as possible after the closing voltage
test so that the thermal stabilization remains unaltered.
Connect the regulator as shown in FIG 11:8 and
gradually speed up the generator to 4500 rev/min for
approximately 5 minutes. Ensure that the voltmeter reads
at least 14.5 volts and then gradually reduce the generator
speed carefully watching the movement of the ammeter
needle which should at first indicate a charging current
and then gradually move to zero and then to the other side
of the scale to indicate reverse current value. If the
generator speed is reduced further the reverse current
reading will increase to a given value and then suddenly
fall to zero which will indicate that the cut-out contact
has opened. This limit indicates the maximum reverse
current value which should not, under any circumstances,
exceed 16 amps.
During this test, to obtain the maximum reverse
current possible the reduction in generator speed must
not take more than 10 seconds otherwise the battery
voltage will drop excessively.
Checking voltage regulator:
This test should be carried out w i t h the regulator under
half load and at a temperature of 50°± 3°C. Connect the
regulator as shown in FIG 11:9 and operate the regulator
for approximately 30 minutes by supplying a current half
that of regulated current which is 1 6 ±5 amp. Once the
regulator has been brought to the required temperature
stop the generator and start it again, gradually increasing
the speed to a maximum of 4500 rev/min. Adjust the
rheostat for a generator output corresponding to half load
current of 8 ± 2 amps. When this generator output has
been set the voltage should be 14.2± .3 volts.
Checking current regulator:
Leave the regulator connected as shown in
FIG 11 :10
and this test must be carried out immediately after testing
the half load regulated voltage of the voltage regulator
when connected to a battery. Check that the ammeter
fitted will accommodate a 40 amp deflection: if not a
F500117
FIG 11 :9 Wiring diagram for checking the current and
voltage regulators
Key to Fig 11:9 GR Regulator GN 1.1 2.1 6 G Generator
FIAT D 90.12.16.3 V Voltmeter, 20 V scale (0.5% accuracy)
A Ammeter, 20 A scale (to check voltage regulator) and 40 A
scale (to check current regulator)
B Battery, 50 Ah, fully chargedR Rheostat, 25 A. 3
FIG 11 :10 Wiring diagram for setting the cut-out relay
Key to Fig 11 :10 B 2 V battery B 20 V batteryA Ammeter, 20 A scale ( 1 % accuracy) V Voltmeter, 20 V
scale (0.5% accuracy), directly connected to terminals 31—51
P Potentiometer for voltage adjustment, having such a capacity
that the current draw of the cut-out shunt winding does not
cause sensible variations in the voltage readings (voltmeter
under no load) S Test lamp, with 2 V, 3 W bulb, to signal
opening and closing of contacts R Rheostat, 4 12
AR Voltage drop resistor, suitable to allow turning on of A withT open and cut-out contacts open
Setting of instruments before inserting the unit: P At
minimum (voltmeter reads zero) T Open R All inserted
(max. resistance) T Open
FIG 11:11 Wiring diagram for setting the voltage and
current regulators
Key to Fig 11 :11 GR Regulator assembly GN 1.12.16
G Generator D 90.12.16.3 V Voltmeter, 20 V scale (0.5%
accuracy) A Ammeter, 20 Amp. scale (for voltage regulator),
or 40 Amp. scale (for current regulator) R Rheostat, 25
Amps., 3 Ohms B 50 Amp/h battery, fully charged I Switch

Checking cut-out:
1 Closing voltage:
This test should be carried out at a temperature of
25°±10°C and the regulator should be connected to a
generator test bed as shown in FIG 11:7. The unit should
be operated under no load conditions for between 15 -
18 minutes with the cover installed and w i t h a voltage of
between 16.5 volts for an initial operating temperature of
15-20°C or 15 volts for an initial operating temperature
of 20-35°C. This will enable thermal stabilization of the
unit to be obtained so that the temperature of both the
cut-out shunt windings and the bymetallic springs
increase due to the heat developed by the windings and
reaches the normal operating setting.
Once thermal stabilization has been obtained the
generator should be restarted and the speed gradually
increased so that immediately the test lamp starts to
glow the voltmeter reading may be taken. This will be
the value of the cut-out contact closing voltage.
2 Reverse current:
This check should be carried out at a temperature range
of between 25°±10°C and it is recommended that it is
performed as soon as possible after the closing voltage
test so that the thermal stabilization remains unaltered.
Connect the regulator as shown in FIG 11:8 and
gradually speed up the generator to 4500 rev/min for
approximately 5 minutes. Ensure that the voltmeter reads
at least 14.5 volts and then gradually reduce the generator
speed carefully watching the movement of the ammeter
needle which should at first indicate a charging current
and then gradually move to zero and then to the other side
of the scale to indicate reverse current value. If the
generator speed is reduced further the reverse current
reading will increase to a given value and then suddenly
fall to zero which will indicate that the cut-out contact
has opened. This limit indicates the maximum reverse
current value which should not, under any circumstances,
exceed 16 amps.
During this test, to obtain the maximum reverse
current possible the reduction in generator speed must
not take more than 10 seconds otherwise the battery
voltage will drop excessively.
Checking voltage regulator:
This test should be carried out w i t h the regulator under
half load and at a temperature of 50°± 3°C. Connect the
regulator as shown in FIG 11:9 and operate the regulator
for approximately 30 minutes by supplying a current half
that of regulated current which is 1 6 ±5 amp. Once the
regulator has been brought to the required temperature
stop the generator and start it again, gradually increasing
the speed to a maximum of 4500 rev/min. Adjust the
rheostat for a generator output corresponding to half load
current of 8 ± 2 amps. When this generator output has
been set the voltage should be 14.2± .3 volts.
Checking current regulator:
Leave the regulator connected as shown in
FIG 11 :10
and this test must be carried out immediately after testing
the half load regulated voltage of the voltage regulator
when connected to a battery. Check that the ammeter
fitted will accommodate a 40 amp deflection: if not a
F500117
FIG 11 :9 Wiring diagram for checking the current and
voltage regulators
Key to Fig 11:9 GR Regulator GN 1.1 2.1 6 G Generator
FIAT D 90.12.16.3 V Voltmeter, 20 V scale (0.5% accuracy)
A Ammeter, 20 A scale (to check voltage regulator) and 40 A
scale (to check current regulator)
B Battery, 50 Ah, fully chargedR Rheostat, 25 A. 3
FIG 11 :10 Wiring diagram for setting the cut-out relay
Key to Fig 11 :10 B 2 V battery B 20 V batteryA Ammeter, 20 A scale ( 1 % accuracy) V Voltmeter, 20 V
scale (0.5% accuracy), directly connected to terminals 31—51
P Potentiometer for voltage adjustment, having such a capacity
that the current draw of the cut-out shunt winding does not
cause sensible variations in the voltage readings (voltmeter
under no load) S Test lamp, with 2 V, 3 W bulb, to signal
opening and closing of contacts R Rheostat, 4 12
AR Voltage drop resistor, suitable to allow turning on of A withT open and cut-out contacts open
Setting of instruments before inserting the unit: P At
minimum (voltmeter reads zero) T Open R All inserted
(max. resistance) T Open
FIG 11:11 Wiring diagram for setting the voltage and
current regulators
Key to Fig 11 :11 GR Regulator assembly GN 1.12.16
G Generator D 90.12.16.3 V Voltmeter, 20 V scale (0.5%
accuracy) A Ammeter, 20 Amp. scale (for voltage regulator),
or 40 Amp. scale (for current regulator) R Rheostat, 25
Amps., 3 Ohms B 50 Amp/h battery, fully charged I Switch

FIG 11:12 Wiring diagram for setting the cutout relay
Key to Fig 11 :12 B 2 V battery B 20 V battery
A Ammeter, 15 A scale ( 1 % accuracy) V Voltmeter, 20 V
scale (0.5% accuracy), directly connected to terminals 31-51
P Potentiometer for voltage adjustment, having such a capacity
that the current draw of the cutout shunt winding does not cause
sensible variations in the voltage readings (voltmeter under no
load) S Test lamp, with 2 V, 3 W bulb, to signal opening
and closing of contacts R Rheostat, 4 , 1 2 A R Voltagedrop rheostat, suitable to allow turning on of S with T open and
cutout contacts open
Setting of instruments before inserting the unit: P At
minimum (Voltmeter reads zero) T Open R All inserted
(max. resistance) T Open
1
2
3
4
5
6
FIG 11:13 Location of electrical system fuses
Key to Fig 11 :13 1 Fuse N o . 30.2 2 Fuse N o . 30.3
3 Fuse N o . 56.b1 4 Fuse N o . 56.b2 5 Fuse N o . 15.54
6 Fuse N o . 30
meter w i t h a fuller scale deflection of 40 amp must be
substituted. Adjust the rheostat to give maximum
resistance and operate the regulator for approximately
30 minutes with regulator controlled current and 13 volt
supply. The resistor R of the rheostat should be adjusted
until the current is steady whilst the voltage drops. This
will indicate that the unit has reached normal operating
temperature. Stop the generator, restart it and speed up
gradually to 4500 rev/min. Check that the regulated
current value corresponds to the specified value of
1 6± .5 amps. By continually reducing the resistance the
current should remain constant. The voltage however
should decrease to as l o w as 12 volts.
118
Cut-out relay adjustment:
Ascertain the type of regulator fitted and then wire to
the test unit as shown in FIG 11:10 or FIG 11 :12.
Before the unit is assembled to the test bed the instru-
ments should be set as follows:
P - at minimum so that voltmeter reads zero.
T — open.
R - all inserted giving maximum resistance.
T - open.
1 Contact closing voltage:
This test should be carried out at an ambient tempera-
ture of 25°±10°C. Close the switch T and stabilize the
regulator thermally by feeding current into it for approxi-
mately 15 to 18 minutes at 16.5 volts which is obtained
by adjusting P for initial regulator operating temperatures
of between 15°-20°C or at 15 volts for initial operating
temperatures of 20°-35°C. Once the stabilizing of the
regulator has been completed bring the voltage to 12 6±
.2 volts by adjusting P. Adjust the load on the setting
spring by bending the relevant arm until the pilot light S
is extinguished. Reset P to m inimum and again increase
the voltage by P and check that the pilot lamp is extin-
guished at the specified voltage.
2 Reverse current:
This test must be carried out at a temperature of
25°± 10°C and it is recommended that it is carried out as
soon as possible after the closing voltage test so as to
maintain minimum regulator thermal stability. With the
switch T closed bring the voltage to 14.5 volts by
operating P. The contacts of the cut-out should be closed
and the pilot lamp S off. Close T and increase the reverse
current by means of the rheostat R and check that the
pilot lamp S glows as the contacts part. The opening may
also be unsteady which will be indicated by a slight
buzz from the unit. Check the value of the ammeter of the
reverse current causing the opening of the contacts and
this should not exceed 16 amps. If the reading is unstable
or S lights up at the recommended limit reset the reverse
current to the minimum value and repeat the test once
more. Finally open the switches T and T and again
adjust rheostat R and P to the minimum settings.
Voltage regulator adjustment:
This test should be carried out at a temperature of
5 0 ° ±3 ° C . Connect the unit as shown in FIG 11 :11 and
load the voltage regulator adjusting springs by bending
the relevant arm. With the unit at the required test
temperature close 1 start the generator and stabilize
the regulator thermally by feeding a current for 30
minutes at 15 volts, which is obtained by adjusting the
generator speed. The generator should then be stopped,
I opened and the generator restarted and gradually
speeded up to 4500 rev/min. The voltage regulator
spring load adjustment should be set by suitably bending
the relevant adjusting arm and by rheostat R so as to have
a voltage of 14.2±.3 volts and a half load current of
8 ± 2 amps. Finally check the steadiness and accuracy
of the voltage regulator setting by stopping the generator
and restarting after approximately 2 minutes and gradually
speeding up to 4500 rev/min.

WINDSHIELD WIPER
MOTOR ASSY
WIPER MOTOR SCREWS
WIPER MOTOR BRACKET
FIG 11:15 Arrangement of windshield wiper unit on
vehicle
B M INT F
SC12 V
31
D
A
SWITCH PARKING
0 ON
SWITCH LEVER POSITIONS
FIG 11:16 Windshield wiper wiring diagram
Key to Fig 11 :16 A Series winding B Shunt winding
D Switch M Motor S Additional winding F INT
C =Terminals
120signal lamp pairs. The flasher unit connections are in
FIG 11:14 and the unit is of the hot wire type.
Faulty operation of flashers:
In cases of trouble check the bulb for broken filaments.
Refer to the wiring diagrams in Technical Data and check
all flasher circuit cables and connections. Check the
appropriate fuse. Switch on the ignition and check w i t h
a voltmeter between flasher unit positive terminal and
earth to see if battery voltage is present. Connect together
flasher unit positive terminal and L and operate the
direction indicator switch. If the flasher lamps now light,
the flasher unit is defective and must be renewed. It is not
possible to dismantle and repair a faulty flasher unit.
Before removing make a note of the connections so that
they will be replaced correctly when the new unit is being
installed.
Before making the connections it is advisable to check
the circuits to ensure that the new flasher unit is not
damaged by wrong connection. Test by joining the
cables normally connected to the unit and operate the
switch. If the connections are wrong the appropriate
fuse will blow but no damage will be done to the flasher
unit.
Never insert terminal L directly to earth without having
first connected in series the bulbs specified, otherwise
the flasher unit will be damaged. For the same reason
terminal L must never be shorted to ground nor must there
by any short circuits in any of the leads from the L
terminal to the bulbs. The flasher unit must never receive
blows of any kind since it is a very delicate component
and easily damaged.
11:8 Windscreen wipers
Description:
The windscreen wiper assembly comprises a motor
unit that drives t w o wiper blades through a reduction
gearing and mechanical linkage. The reduction gear
includes a worm screw on the motor armature shaft and a
helical pinion. The motor, left blade pivot and linkages
are mounted on a sheet metal bracket, whilst the right
blade pivot is connected to the main drive link. When
assembled to the vehicle the right blade pivot is fixed
directly onto the body. The unit is provided w i t h an
automatic parking device which ensures that the blades
return to their correct park position. The w
indscreen wiper
is- controlled by a lever switch with three separate
positions on earlier models or a simple on-off switch on
later models.
Maintenance:
Maintenance is confined to the changing of the wiper
blades when they have deteriorated and occasional
lubricating of the mechanical linkage.
Wiper unit faulty operation :
1 It is important that the wiper unit assembly is correctly
fitted to the body otherwise distortion of the wiper
mounting bracket can occur which will cause
abnormal stresses on the pivot and linkages resulting
in irregular and difficult blade sweep.
2 If the blades keep on sweeping at a reduced speed
although the switch lever has been pressed to the

BOW
FIG 12:17 Sun Roof top in unlatched position
FIG 12:18 Diagrammatic view of car heating system
Key to Fig 12 :18 1 Thermostat controlling shutter 2 Shutter, engine cooling air outlet 3 Lever, heater hand control
4 Warm air outlet slots 5 Demister valve control knobs 6 Windshield demister diffusers
NOTE—The car may be also equipped, optionally, with a heating booster as shown in FIG 12:19
134
4 Rear moulding for the top lining mounting onto the
rear metal panel.
5 Top lining retaining strap which is secured to the front
end of t h e rear metal panel using a bridge bracket.
6 Bracket for strap which hooks up the top lining when
in the folded position.
Dismantling and reassembly is a straightforward
operation providing that careful note is made of the
location of all screws that are removed. To reassemble
it is suggested that the rear metal panel is mounted on
the body shell first. The collapsible top assembly is then
positioned and secured to the rear metal panel using eight
rivets. The top covering should be stretched to the closed
position and secured to both framing side arms to t h e
body shell wells using the special screws. 500F and L
models are similar, but with a single central sun roof latch:
t h e rear metal panel is no longer removable.
12:13 Seats
Front seats:
The front bucket seats comprise a one-piece tubular
frame covered with imitation leather or cloth padded

cushion and back rest. A number of rubber straps are
hooked across the frame under the cushion and in a
sheath covering on the seat back.
The bottom of the front seat frame ends are provided
with sliding guides which run in guide rails attached to
the floor. The sliding guides are pivoted on the frame
tubes to allow for forward tilting of the seats giving better
access to the rear compartment. Two rubber pads
provide cushioning of the seat frame on the guide rails
as shown in FIG 12:11. The control lever for seat
adjustment is fitted in the frame righthand tube to permit
unlocking of the seats so that they may be adjusted to
individual drivers requirements.
Rear seats (Sedan):
The rear seat comprises of a foam rubber cushion and
back. The seat back is cemented to the rear floor and
body shell bulkhead. The rear seat lining is of fabric and
imitation leather. The seat lining is held in place by four
self-tapping screws, t w o of which secure the floor below
the back window and two the lining at the base of t h e
back rest. Included with the seat assembly is a masonite
floor which is fitted below the rear window.
Rear Seat (Station Wagon):
The rear seat back rest is pivoted at the base of its
frame so that it can be folded down to form a load plat-
form surface. In the upright position it is retained in place
by t w o brackets mounted on either side of the body below
the side
windows.
12:14 Interior heater
Description:
Interior heating is accomplished by recirculation of
warm air from the engine cooling system through engine
cowling. Referring to FIG 12:18 a hose conveys warmed
air from the engine cowling to the centre tunnel floor
where warm air flows out through two slots being cut on
the windshield delivery hoses. Air admission can be
adjusted by turning the control lever to the right which
operates the tunnel throttle valve at the rear seat.
The heating system may be fitted with a booster which
comprises a casing on the front exhaust pipe being
connected to the engine cowling and the warmed air
passage tunnel. Warm air flowing to the car interior is
heated to higher temperature than that from the standard
version of heater (see FIG 12:19).
Windshield demisting:
As will be seen from FIG 12:18, t w o air hoses w i t h
throttle valves for airflow control are relayed from a casing
F500135
FIG 12:19 Diagram of booster
Key to Fig 12:19 1 Thermostat controlling shutter
2 Car interior heater booster 3 Hand control unit
in front of the centre of the floor tunnel. Flexible hoses
are connected to two air diffusers which are located on
the instrument panel and parallel to the windshield glass.
When the throttle valves 5 (see FIG 12:18) are operated
through the two control knobs, warmed air is directed
onto the windshield glass so preventing misting, frosting
or icing in adverse weather conditions.
Inspection:
Ensure that t h e lever, the lever spring and butterfly
valve hinge are not distorted. Check that the ducting to
the tunnel as well as the upper and lower hoses are air-
tight which if not, should be renewed.