Testing and repairing wiring/lighting system

OPERATION SHEET

Operation Title: Test Electrical System of Open and Short Circuit to determine
faults.

Purpose: To locate electrical circuit faults by using Ohmmeter

Equipment, Tools Auto electrical mock-up / vehicle
and Materials Ohmmeter, Battery 12 V long nose pliers, diagonal cutting pliers,
standard screw driver, Phillips screw driver, Auto wire # 10, 3
meters

Procedure: 1. Set the VOM to Xl and set this pointer to 0 by adjusting 0 OHM
Adjuster

Test the following circuit for continuity test:

1.1 Headlight and tail light circuit. If the circuit is okay, there is
continuity in the circuit. If no continuity, check the circuit one by
one until you have located the fault.

1.2 Signal and park light circuit. If okay, the VOM pointer will deflect.
If not, check the system one by one to locate the fault.

Precautions: Never energize the circuit when testing continuity the VOM will be
damaged.

Shut off all switches

Note: If the bulb lights, there is a short in the circuit. Unhook one circuit at a time.
When the light goes out, you have found the short.

Here’s how:
a. Turn on the ignition
b. Turn on all switches in the circuit.
c. Check to see which components work.
d. Use a test light to see if voltage is available to the circuit.
e. If voltage is available to the circuit, but not the component:
• Check connectors at the fuses
• Junction blocks
• Switch terminals
f. Move the test prod along the component wiring (see Figure 4).

Note: Move from system until the open circuit is found with the battery toward the
component.

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 47
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

OPERATION SHEET

Operation Title: Test electrical System of Open and Short Circuit for Fault

Purpose: To locate electrical circuit fault by using VOM

Equipment, Tools Auto-electrical mock-up I Vehicle, Test Lamp, storage

and Materials Battery 12 V, Long nose pliers, Diagonal-cutting pliers,

Procedure: 1. Set the VOM to Xl and set the pointer 0 by adjusting 0 Ohm adjuster.
Test the following circuit for continuity test:

1.1 Head light and tail light circuit. If the circuit is okay there is
continuity in the circuit. If no continuity check the circuit one by
one until you found the fault.

1.2 Signal and park light circuit. If okay the VOM pointer will deflect.
If not check the system one by one to locate the fault.

Precaution: Never energize the circuit when testing continuity. The VOM will be
damage.

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 48
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

SELF CHECK

1. Identify tools and equipment use in locating fault in auto-electrical circuit.
2. Demonstrate how to use the following testing instrument:

• Test Lamp
• VOM - test for continuity test
• VOM - test for voltage
3. Draw the schematic diagram in the following circuit:
4. Using the test light, locate the trouble of the head light circuit; line from ignition
switch to the fuse box has output voltage. What is the trouble?
5. Find the missing electrical part in the signal / park light circuit. below.

6. What will be the trouble in the signal light circuit if two right bulbs front and rear
blink but very low beam?

7. Giving you the complete schematic diagram of the signal and park circuit.
Identify what circuit of the two is functional.

8. What part of the electrical system use to operate the hazard circuit?
9. How would you know if the signal flasher is defective?
10. If the casing of the signal / park light is made of plastic material, what will

happen?

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 49
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

Qualification : Automotive Servicing NC I
Unit of Competency
Module Title : Test and Repair Wiring/Lighting System
Learning Outcome #5
: Testing and Repairing Wiring/Lighting System

: Carry out necessary repairs in the electrical
wiring/lighting system

Assessment Criteria:

1. Procedure in repairing electrical system is enumerated.
2. Necessary repairs are carried out using appropriate tools, technique

and materials.
3. Electrical systems are repaired without causing damage to workplace,

property or vehicle

Resources:

Books
• Checking I replacing fuses, relays, bulbs.
• Checking servicing batteries
• Checking / replacing switches and gauges
• Diagnose electrical circuit diagram
• Checking / adjusting headlight focus
• Service auto battery
• Fundamentals of Electricity
• Battery construction description
• Battery component parts function and construction
• Motor Automotive Technology

By: Anthony E. Schwaller
• Training Aids

- Electrical mock-up
- Circuit diagram (Electrical Wiring Diagram)
- Transparencies
• Service manual

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 50
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

LEARNING EXPERIENCES

Learning Outcome # 5: Carry out necessary repairs in the electrical wiring/
lighting system

Learning Activities Special Instructions

1. Following procedure in repairing • Refer to manufacturers service manual
electrical system. in carrying out repairing electrical
system.

2. Dismantling / installing lighting system • See operation sheet.
accessories.

3. Fitting accessories and making • Fit the accessories based on the
connections. original setting / position.

4. Repairing / replacing defective • Make a test for suspected or found
electrical lighting accessories with fault with the use of appropriate tools,
appropriate tools, materials, and
techniques. materials and techniques, use test
lamp, VOM.

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 51
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

Operation Title: OPERATION SHEET

Dismantling/Installing Lighting Accessories

Purpose: Dismantling/installing lighting accessories is necessary in order to
facilitate job operation.

Conditions or Dismantling/installing should be done in accordance with
Situation for the manufacturers procedure specs.
Operation:

Equipment, Tools • Flat screwdriver
and Materials: • Phillips driver
• Long nose pliers
• Electrical pliers
• VOM
• Test lamp

Procedure: 1. Identify the lighting circuit being disassemble
2. Identify wiring colors.
3. Check installation if not defective.
4. Label each wire for easy identification when installing.
5. Test for continuity of the circuit.
6. Test for resistance (circuit)

Precautions:

Extra care and caution should be observed when removing and installing
light bulbs.

Quality Criteria: Check first bulbs before installation.
1. Clean terminal connections.
2. Exposed wire without insulation should be covered I taped.
3.

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 52
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

LEARNING EXPERIENCES

Learning Outcome # 5: Carry out necessary repairs in the electrical
wiring/lighting system

Learning Activities Special Instructions

1. Procedure in repairing electrical • For more information about repair in

system. the electrical system read the

a. Locate the fault. reference listed below.

b. Identify tools needed in the repair of • Motor Automotive Technology

electrical system • Automotive Symbols and Circuit

• Have you tired repairing Diagram

electrical system following • Fundamental of Electricity

specific procedure? • Diagnose Electrical Circuit Diagram

• What kind of electrical repair • Electrical Troubleshooting

system have you done?

• Have you learned or developed

skills in repairing electrical

system by following systematic

procedure?

2. Dismantling/installing lighting system • Fundamentals of Electricity
accessories. • Motor Automotive Technology
• Have you experience dismantling/
installing lighting accessories?
• What accessories are dismantled/
installed in the lighting system.
• After reading the reference answer
self check and compare your
answer with the answer key.

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 53
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

SELF CHECK

1. What procedure have you used in repairing electrical system?
2. If you use another procedure, state advantage and disadvantage over each other.
3. Identify tools used in dismantling and installing lighting system
4. List down lighting system accessories to be dismantled and to be installed
5. How do you determine whether an accessory is properly fitted?
6. With the use of VOM, test lamps test each accessory for correct connection.
7. Check each accessory for proper connection.
8. How do you check a busted fuse?
9. How do you check a busted bulb?
10. What are the testing materials used in testing busted bulb.
11. Enumerate the lighting circuit.
12. Enumerate / identify tools and materials used in repairing / replacing defective

electrical lighting.

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 54
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

PERFORMANCE TEST

Learner’s Name Date: Test Attempt
Competency: Install Automotive Lighting System 1st 2nd 3rd

Directions: OVERALL EVALUATION

CALL INSTRUCTOR, ask instructor Level
to assess your performance in the
following critical task and Achieved PERFORMANCE LEVELS
performance criteria below.
4 – Can perform this skill without supervision and with
You will be rate based on the overall initiative and adaptability to problem situations.
evaluation on the right side.
3 – Can perform this skill satisfactorily without
assistance or supervision.

2 – Can perform this skill satisfactorily but requires some
assistance and/or supervision.

1 – Can perform parts of this skill satisfactorily, but
requires considerable assistance and/or supervision.

Instructor will initial level achieved.

PERFORMANCE STANDARDS Yes No N/A

For acceptable achievement, all items should receive a “Yes”

or “N/A” response.

1. Was installation of lighting system achieved without causing damage to

any workplace, property or vehicle?

2. Were correct information accessed and interpreted from appropriate

manufacturer’s specification?

3. Were electrical system component installed and wired up using

appropriate tools, materials and equipment?

4. Were the electrical devices such as switches, lights, fuse boxes and

relays installed according to location?

5. Were wirings leading to different lighting components and other devices

installed according to arrangement?

6. Were lead terminals properly insulated, soldered and crimpled?

7. Were the lighting components being connected operational?

8. Was occupational health and safety practices observed throughout the

activity?

9. Testing is completed without causing damage to any workplace or

vehicle.

10. Is the procedure for testing and interpreting schematic diagram done in

accordance with manufacturer specification?

11. Testing of fault and defect carried out using the appropriate tools and

technique.

12. Is the procedure in repairing electrical system enumerated?

13. Is the necessary repairs carried out using appropriate tools, techniques
and materials?

14. Is electrical system repaired without causing damaged to workplace
property or vehicle?

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 55
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

Learner’s diary

DIARY NOTES

Record important dates, jobs undertaken and other workplace events that will assist you in
providing further details to an Assessor.
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Record of Achievement

Module: Testing and Repairing Wiring/Lighting System

LO 1 : Principle of Auto Electricity

Assessment Criteria:

1. OHMS Law explained
2. Circuitry drawn/traced
3. Signs and symbols interpreted
4. Sizes of wire identified according to job requirement
5. Polarity, conductor & insulator determined
6. Law of magnetism explained

Comments:
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Learner has satisfied the above performance criteria.
Learner signature: ........................................................................
Trainer signature: .........................................................................
Date:.............................................................................................

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 57
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

Record of Achievement

Module: Testing and Repairing Wiring/Lighting System

LO 2 : Identify components of Auto lighting system and explain its function

Assessment Criteria:
1. Component parts of the lighting system identified
2. Functions of every lighting system parts explain
3. Occupational Health and Safety practices enumerated

Comments:
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Learner has satisfied the above performance criteria.
Learner signature: ........................................................................
Trainer signature: .........................................................................
Date:.............................................................................................

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 58
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

Record of Achievement

Module: Testing and Repairing Wiring/Lighting System

LO 3 : Install wiring/lighting system

Assessment Criteria:
1. Lighting system circuiting drawn and interpreted
2. Electrical devices such as switches, lights, fuse boxes installed
3. Wiring leading to different lights and other relevant devices installed
4. Lead terminals of wires soldered/crimped

Comments:
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Learner has satisfied the above performance criteria.
Learner signature: ........................................................................
Trainer signature: .........................................................................
Date:.............................................................................................

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 59
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

Record of Achievement

Module: Testing and Repairing Wiring/Lighting System

LO 4 : Test electrical system of open and short circuit to determine faults

Assessment Criteria:

1. Test completed without causing damage to workplace I vehicle.
2. Correct procedure for testing and interpreting schematic diagram in accordance with the

manufacturers’ specification.
3. Testing carried out and faults I detects determined using appropriate tools and techniques.

Comments:
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Learner has satisfied the above performance criteria.
Learner signature: ........................................................................
Trainer signature: .........................................................................
Date:.............................................................................................

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 60
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

Record of Achievement

Module: Testing and Repairing Wiring/Lighting System

LO 5 : Carry out necessary repairs in the electrical wiring I lighting system

Assessment Criteria:
1. Procedure in repairing electrical system enumerated.
• Correct information assessed and interpreted.
• Necessary repair carried out using appropriate tools techniques and materials.
• Electrical systems required without causing damage to workplace, properly or vehicle.

Comments:
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Learner has satisfied the above performance criteria.
Learner signature: ........................................................................
Trainer signature: .........................................................................
Date:.............................................................................................

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 61
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

TERMS AND DEFINITIONS Fusible Link - A wire made of meltable
material with a special heat-resistant
A circuit - A generator circuit that uses an insulation. When there is an overload
external grounded field circuit. The in the circuit, the link melts and opens
generator is on the ground side of the the circuit.
field coil.
Ground - The common negative connection
Ammeter - A test meter used to measure of the electrical system that is the
current draw. point of the lowest voltage.

Amperes - See current. Grounded Circuit - An electrical defect that
Analog - A voltage signal that is infinitely allows current to return to ground
before it has reached the intended
variable or can be changed within a load component.
given range.
Backup Lights - A light that illuminates the Ground Side – The portion of the circuit that
back of the car when the transmission is is from the load component to the
shifted in reverse. negative side of the source.
Battery - An electrochemical device for
storing energy in chemical form. Hazard Warning Lamp - A light that warns
Battery Terminal Test - Checks for poor an approaching driver of the presence
electrical connections between the of a vehicular hazard by flashing all
battery cables and terminals. Use a turn signal lights together.
voltmeter to measure voltage drop
across the cables and terminals. Headlamp - A lamp that provides a bright
Bench Tests - A term used to indicate that light ahead of a vehicle.
the unit is to be removed from the
vehicle and tested. Insulator - A substance that is not capable
Circuit - The path of electron flow consisting supporting the flow of electricity.
of the voltage source, conductors, load
component, and return path to the Lamp - A device that produces light as a
voltage source. result of a current flow through a
Conductor - A substance that is capable of filament. The filament is enclosed
supporting the flow of electricity through within a glass envelope and is a type
it. of resistance wire that is generally
Continuity - Refers to the circuit being made from tungsten.
continuous with no open.
Current - The aggregate flow of electrons License Lights - A light used to illuminate a
through a wire. One ampere represents license plate on the rear of a vehicle.
the movement of 6.25 billion electrons
(or one column) past one point in a Ohm - A unit of measure for resistance. One
conductor in one second. ohm is the resistance of the conductor
Dimmer-switch - A two-position switch such that a constant current of one
operated by the driver to select high or ampere in it produces a voltage of one
low headlight beam. volt between its ends.
Electrical Load - The working device of the
current. Ohmmeter - A test meter used to measure
Electromagnetism - A form of magnetism resistance and continuity in a circuit.
that occurs when current flows through
a conductor. Ohm’s Law - Defines the relationship
Electromotive Force (EMF) - See voltage. between current, voltage and
Flasher - An automatic reset circuit breaker resistance.

used in the directional signal and Open Circuit - A term used to indicate that
hazard warning circuits. current flow is stopped. By opening
Fuse - A replaceable circuit protection device the circuit, the path for electron flow is
that will melt should the current broken.
passing through it exceeds its rating.
Overload - Excess current flow in a circuit.
Parallel Circuit - A circuit that provides two or

more paths for electricity to flow.
Parking Lights - A light that marks the front

of a parked vehicle, and to mark the
front of a vehicle if a headlamp fails.

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 62
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

Polarity - The quality of an electric State of Charge - The condition of a battery’s
component that determines the electrolyte and plate materials at any
direction of the current. given time.

Relay - A device that uses low current to Taillights - A red light found at the back of
control a high current circuit. Low the vehicle.
current is used to energize the
electromagnetic coil, while high Turn Signal Lights - A light which indicates
current is able to pass over the relay an intended change in direction by
contacts. flashing lights on the side towards
which the turn will be made.
Resistance - Opposite of current flow.
Series Circuit - A circuit that provides a Voltage - The difference or potential that
indicates an excess of electrons at the
single path for current flow from the end of the circuit the farthest from the
electrical source through the circuit’s electromotive force. It is the electrical
components, and back to the source. pressure that causes electrons to
Series-parallel Circuit - A circuit that has move through a circuit. One volt is the
some loads in series and some in amount of pressure required to move
parallel. one amp of current through one ohm
Short -An electrical fault that allows for of resistance.
electrical current to bypass its normal
path. Voltage Drop - A resistance in the circuit that
Splice - The joining of single wire ends or the reduces the electrical pressure
joining of two or more electrical available after the resistance. The
conductors at a single point. resistance can either be the load
component, the conductors, any
connections, or unwanted resistance.

Code No. TESTING AND REPAIRING Date: Developed Date: Revised Page 16
ALT723305 WIRING/LIGHTING SYSTEM Oct. 25, 2003 June 11, 2004

ACKNOWLEDGEMENT

Copyright TESDA
Centex: RTC 5 – Camarines Sur

First Published OCTOBER 2003

This draft was prepared at the Competency-Based Learning Materials
Development Workshop conducted at the Cagayan de Oro (Bugo) School of Arts
& Trades, from 23rd to 27th October 2003.

It was based on the competency standard for Automotive Service Technician
developed by the Skill Standard and Certification Office (SSCO), and the
Competency-Based Curriculum Instructional Modules developed by the National
Institute for Technical Vocational Education and Training (NITVET), Technical
Education and Skills Development Authority (TESDA).

Some materials for contextual learning (science, math and communication) were
supplied by Academic Teachers from different TESDA-supervised schools.

This learning instrument was developed by the following personnel:

Technology Instructors :Maximo B. Bongat
Academic Teachers: Roberto A. De Las Llacias, Mario P. Cuña.

Leonardo M. Montero. Aileen B. Archinue
RTC Administrator: Noel R. Diaz
Vocational Institution Supervisor: Romeo M. Hernandez
Facilitator: Santiago S. Esquivel

This work was produced with funding provided by TESDA.

REFERENCE AND FURTHER READING

1. Automotive Technology - Body Electrical System

2. Automotive Mechanics; 10th edition, Crouse & Anglin

Code No. Module INSTALLING AUTOMOTIVE LIGHTING SYSTEM Date: Developed Date: Revised Page 2 of 50

AST-NC2-C3.1 LO1: Explain the Principle of Auto Electricity Oct. 25, 2003