Transcript Lighting circuits File

Level 3 Lighting circuits
Typical Side/Rear Lights Electrical Schematic
OFF position - all lights off.
Battery
Fuse
Headlight
switch
Side lights
License
plate
lights
Rear lights
PARK position - side and rear lights on.
HEAD position - side and rear lights on.
Next >
Typical Side/Rear Light Electrical Schematic
When the headlight switch
is in the OFF position, all
lights are off.
When the switch is in
the PARK position,
the side and rear
lights are on.
License
plate
lights
Battery
Fuse
Headlight
switch
Rear
Side
Rear
Side
Switch in run position,
rear and side lights on
When the switch is in the
HEAD position, the side
and rear lights are on.
Typical Headlight Electrical Schematic
When the headlight switch is in the
OFF position, all the lights are off.
When the switch is in the
PARK position, the vehicle’s
side and rear lights are on.
When the switch is in the HEAD
position, power is supplied to the
main / dip beam switch. The
position of this switch determines
which lights are on.
Indicator and Hazard Warning Lights
Indicator Lights
Indicator lights indicate
direction change.
Bulbs normally SBC type.
Bulb must be capable of flashing
on and off, for long periods.
Next >
Flasher Unit
Indicator flash rate must be constant.
Produced by a device known as a
flasher unit.
Usually contained in relay / fuse
box, under the dashboard.
Next >
Flasher Unit - Bimetal Type
Bimetal strip and
heating element.
Turn signal switch set to
on, current flows through
heating element,
warming bimetal strip.
12V in, from
indicator switch Bimetal
strip
To indicator
lights
Contacts
Bimetal strip bends,
contacts open, lights off.
While contacts are open,
heating element and
bimetal strip cool down.
Heating element
Bimetal strip returns to original position, contacts close, lights on.
Process repeats until turn signal switch is set to off.
Next >
Flasher Unit - Electronic Type
Main components:
Integrated circuit
Relay
Capacitor
Resistor
Next >
The Integrated Circuit
Oscillator produces
square wave.
C
Bulb failure detector
Square wave
frequency
determined by CR.
Square wave
operates relay
driver.
From ignition
switch
To
indicator
lights
R
Oscillator
Relay driver switches relay on and off,
indicator lights correspondingly flash.
Relay driver
Bulb failure detector doubles flash rate when bulb fails.
Relay
Next >
Hazard Warning Lights
Warn of a possible
emergency or hazard.
Activated by red
push button.
Red hazard
warning button
International
warning triangle
Usually mounted on
steering column.
When pushed down, all
indicator (hazard) lights flash.
Button marked with
international
warning triangle.
Next >
Indicator/Hazard Warning Schematic
Ignition
switch
Hazard switch
Indicator
flasher unit
Indicator switch
Indicator
lights
Battery
Indicator operation: flasher unit receives power via fuse,
ignition switch and normally closed hazard switch contact.
Hazard operation: flasher unit receives power direct from
battery, via fuse and hazard switch contacts.
Next >