1957 FIAT 500 wipers

CHAPTER 11
THE ELECTRICAL EQUIPMENT
11:1 Description
11:2 Battery
11:3 The generator
11:4 The starter
11:5 The control box
1 1 : 6 Fuses
1 1 : 7 Flasher unit
11:1 Description
All models covered by this manual have 12 volts
electrical systems in which the negative battery terminal
is earthed. There are three units in the regulator box to
control the charging circuit; a cut-out, a current regulator
and a voltage regulator. These are adjustable but it must
be stressed that accurate moving coil meters are required
when checking or altering the settings. Cheap and
unreliable instruments will make accurate adjustments
impossible.
There are wiring diagrams in Technical Data at the end
of this manual to enable those with electrical experience
to trace and correct wiring faults.
For t h e U.K. Market the headlamps are of the double
filament dipping renewable bulb type with adjustments
for individual beam settings.
The battery is located in the front compartment
forward of the petrol tank and the fuses to the rear o f the
petrol tank.
Detailed instructions for servicing the electrical equip-
ment will be found in this chapter, but it must be pointed
out that it is not sensible to try to repair that which is
seriously defective, electrically or mechanically. Such
equipment should be replaced by new units which can
be obtained on an exchange basis.
F500111
11 :8 Windscreen wipers
1 1 : 9 The lighting system
11:10 Panel and warning lights
11:11 The horn
11:12 Lighting and flasher switch
1 1 : 1 3 Fault diagnosis
11.2 The battery
This of the 12-volt lead/acid type and has to meet
heavy demands for current particularly in the winter. To
maintain the performance of the battery at its maximum
it is essential to carry out the following operations.
Keep the top of the battery and surrounding parts dry
and clean, as dampness can cause leakage between the
securing clamps and the battery terminals. Clean off any
corrosion from the metal parts of the battery mounting
with diluted ammonia and paint them with an anti-
sulphuric paint. If the terminal posts are corroded,
remove the cables and clean w i t h diluted ammonia.
Smear the posts w i t h petroleum jelly before remaking the
connections and fit the terminals securely. High electrical
resistance due to corrosion at the terminal posts is often
responsible for lack of sufficient current to operate the
starter motor.
Ensure t h a t the filler plugs are in good condition and
show no signs of cracks. This may cause leakage of
electrolyte and consequent corrosion. Test the condition
of the cells after topping-up the electrolyte level with
distilled water to just above the tops of the separators as
shown in FIG 11 :2 . Never add neat acid. If it is
necessary to make a new electrolyte due to loss by
spillage add sulphuric acid to the
distilled water.
It is highly dangerous to add water to acid.

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