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Electrical System
All electrical equipment is of Lucas manufacture with the exception of the Ignition, Starting and
Charging Systems, which are of Chrysler origin. The Electrical system is of the 12 volt NEGATIVE
earth type. Most British and Continental cars employ a Positive earth system, and the difference
must be observed—as INCORRECT POLARITY will cause serious damage to the rectifiers in the
alternator.
Alternator
The alternator takes the place of the usual dynamo. It is an alternating current generator, with six
built-in silicone rectifiers which convert the alternating current into direct current. The alternator
provides a high charging rate at low engine speed, and this means that the battery can be kept
fully charged all the time.
Belt Tension
The belt which drives the alternator and water pump has to be correctly tensioned. If it is too tight it
will load the alternator bearings excessively, causing their early failure ; if too loose, the belt will slip,
causing poor water pump and alternator performance. The belt tension can be checked by pressing
down on it, midway between the water pump and alternator. The deflection should be 1/4" except
where a new belt has just been fitted, when it should be 1/8”.
Battery
The battery is mounted in the engine compartment. The following Lucas battery is fitted and
recommended as a replacement :
Type
BTZ11A
Voltage
12
Capacity
72 Ampere hours
The level of the electrolyte should be checked weekly, or more often in hot weather. If it has fallen
below the top of the separators, sufficient distilled water should be added to bring it to approx. i”
above the separators. It is important not to overfill the battery. The battery is held in its box by two
clamps and four wingnuts. It must always be firmly secured. The terminals should be kept clean and
tight, and well covered in petroleum jelly.
Fuses
Six fuses are used to protect the electrical equipment. The radio, the Selectaride rear dampers, and
the electric cooling fans are individually fused ; the interior light and the bootlight share a low
independent rating fuse, while all other circuits are carried by the two main fuses.
The main fuse box is under a black cover, mounted beneath the facia near to the steering column.
The top fuse is of 50 amp rating, and protects all circuits which operate independent of the ignition.
The lower one, of 35 amp rating, protects all circuits controlled by the ignition. Two spare fuses, one
50 amp and one 35 amp, are provided.
The fuse protecting the interior light and the bootlight is housed in a white nylon in-line fuse holder
adjacent to the main fuse box. This is a 10 amp fuse.
A black nylon in-line fuse holder will be found above the white one. This holds the 15 amp fuse which
protects the Selectaride Rear Dampers.
The 5 amp fuse for the radio is mounted below the radio itself. Access to it is gained by removing
the central instrument panel. The engine cooling fans are protected by a fuse in the relay box on
the bulkhead in the engine compartment. This is mounted in a white nylon in-line fuse holder.
Blown Fuses
A blown fuse is indicated by failure of all the items protected by it. These will be shown in the wiring
diagram. Before a fuse is changed, the cause of the trouble should be remedied, or it will blow again.
Fuses should always be replaced by ones of the same rating.