16-11). The operator selects the desired headlamp
beam by moving the lever towards the front or rear. If
this dimmer switch configuration is used with a headlamp
switch that Is also Integrated in the turn signal lever, then
the two switches and the turn signal switch usually are
serviced as one unit.
16-8. Overload Breakers.
Besides limiting the
current by current regulation, the battery and wiring
should be protected against excessive loads that might
occur due to shorts or grounds in the wiring system.
This protection may be secured by a current-limiting
circuit breaker or a single fuse. The location of an
overload breaker In the electrical system is shown in
a. Circuit Breaker (Fig. 16-13).
(1) The circuit breaker is a protective device
designed to open the circuit when excessive current
passes through its windings. All current for lights and
accessories pass through the circuit breaker. It is similar
In construction to the cutout, but opens the circuit rather
Figure 16-8. Turn Signal Lever-Mounted
than closes It. If there is a ground or other trouble in the
circuit, the rush of current will start the circuit breaker.
vibrating and In this way It Indicates that there is
out driving lights. But for stop lights for daylight driving,
something wrong In the system. The device breaks the
or normal bright lights for Ordinary night driving, you
circuit at about 25 amperes but, after opening, allows
must first lift the mechanical switch lever and then turn
only about 5 amperes to pass through, which keeps it
the main switch lever to the right. The auxiliary switch
vibrating. Thus the circuit breaker protects the battery
gives panel lights when the main switch is In any of its
from rapid discharge when trouble develops. The circuit
ON positions. But it will give parking lights only when the
breaker will continue to vibrate until the trouble is found
main switch is in service drive (to the extreme right).
When the main switch is off, the auxiliary switch should
not be moved from the OFF position.
(2) In all types of circuit breakers, the short
circuit must be removed before the breaker can be reset.
b. Dimmer Switch. The dimmer switch is used to
The short circuit can be located easily by disconnecting
control solely the selection of headlamp beams. The
each circuit separately until the circuit breaker stops
main consideration in locating the headlamp switch is the
ease of finding it by the driver without diverting attention
from vehicle operation.
(3) Some automatic breakers do not vibrate,
but have a telltale light placed across the contacts. This
(1) One of the most common locations for the
light, generally placed where it Is visible to the operator,
dimmer switch is on the floor to the left of all of the
is protected by a resistance. When the circuit breaker
control pedals (fig. 16-10). This switch configuration
contacts are opened by excessive current, the light
uses a single metallic button that alternately selects
flashes on. There is generally sufficient current flowing
between headlamp beams each time it is depressed.
through the relay coil with the lamp in series to
(2) Currently, the most popular dimmer switch
configuration is Integrated In then turn signal lever (fig.