Lesson 4/Learning Event 2
To get stop lights for daylight driving, or normal bright lights for ordinary night driving, you must
first lift the mechanical switch lever and then turn the main switch lever to the right. The auxiliary
switch gives panel lights when the main switch is in any of its ON positions. It will give parking
lights only when the 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.
The dimmer switch is used to control solely the selection of headlamp beams. The headlamp
switch should be positioned where it can be easily located by the driver without diverting attention
from vehicle operation.
One of the most common locations for the dimmer switch is on the floor to the left of all of the
control pedals. This switch configuration uses a single metallic button that alternately selects
between headlamp beams each time it is depressed.
Currently, the most popular dimmer switch configuration is integrated in the turn signal lever. 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.
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 circuit breaker is a protective device designed to open the circuit when excessive current passes
through its windings. All current for lights and accessories passes through the circuit breaker. It is
similar in construction to the cutout, but opens the circuit rather 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 something wrong in the system. The device breaks the circuit at about
25 amperes but after opening allows only about 5 amperes to pass