Remove and replace light vehicle electrical units and components

Business Sectors (Suites): Maintenance and Repair - Light Vehicle
Developed by: IMI
Approved on: 30 Mar 2020


This NOS is about removing and replacing units and components previously identified as faulty or damaged or where the customer has requested replacements. It is also about evaluating the performance of replaced units and components. 

The units and components concerned are not those replaced as part of normal routine vehicle maintenance.

Performance criteria

You must be able to:

P1 use suitable personal and vehicle protective equipment throughout all removal and replacement activities
P2 support your removal and replacement activities by reviewing:

P2.1 vehicle technical data
P2.2 removal and replacement procedures
P2.3 legal requirements 
P3 prepare, check and use all the equipment required following manufacturers' instructions
P4 prepare the vehicle systems and work area for safe working procedures, as appropriate to the vehicle
P5 carry out all removal and replacement activities following;

P5.1 manufacturers' instructions
P5.2 your workplace procedures
P5.3 health, safety and environmental requirements
P6 work in a way which minimises the risk of:

P6.1 damage to other vehicle systems
P6.2 damage to other vehicle components and units
P6.3 contact with leakage
P6.4 contact with hazardous substances
P7 ensure replacement electrical auxiliary units and components conform to the vehicle operating specification and any legal requirements
P8 record and report any additional faults you notice during the course of your work promptly
P9 use suitable testing methods to evaluate the performance of the reassembled system accurately
P10 ensure the reassembled system performs to the vehicle operating specification and meets any legal requirements prior to return to the customer
P11 ensure your records are accurate, complete and passed to the relevant person(s) within the agreed timescale and in the format required
P12 complete all removal and replacement activities within the agreed timescale
P13 report any expected delays in completion to the relevant person(s) promptly 

Knowledge and Understanding

You need to know and understand:

Legislative and organisational requirements and procedures
K1 the legal requirements relating to the vehicle (including road safety and refrigerant handling, fuel storage, high voltage or other requirements)
K2 the legislation and workplace procedures relevant to 

K2.1 health and safety
K2.2 the environment (including waste disposal)
K2.3 appropriate personal and vehicle protective equipment
K3 the importance of documenting removal and replacement information
K4 the importance of working to agreed timescales and keeping others informed of progress
K5 the relationship between time and costs
K6 the importance of reporting anticipated delays to the relevant person(s) promptly

Use of technical information

K7 how to find, interpret and use sources of information applicable to electrical units and component removal and replacement
K8 the importance of using the correct sources of technical information
K9 the purpose of and how to use identification codes

Electrical auxiliary system operation and construction

K10 how electrical units and components are constructed, removed and replaced for the classification of vehicle worked upon
K11 how electrical units and components operate for the classification of vehicle worked upon


K12 how to prepare, check and use all the removal and replacement equipment required

Electrical and electronic principles

K13 vehicle earthing principles and earthing methods
K14 electrical and electronic principles associated with electrical systems, including types of sensors and actuators, their application and operation
K15 types of circuit protection and why these are necessary
K16 electrical safety procedures 
K17 how lighting, warning, charging and starter circuits work
K18 electric symbols, units and terms
K19 electrical/electronic control system principles
K20 the hazards associated with working on or near high energy electrical vehicle components

Electrical units and component removal and replacement

K21 how to remove and replace *electrical units and components for the classification of vehicle worked upon
K22 how to test and evaluate the performance of replacement electrical units and components and the reassembled system against the vehicle operating specifications and any legal requirements
K23 the relationship between testing methods and the electrical units and components replaced – the use of appropriate test methods
K24 the manufacturer’s specification for the type and quality of electrical units and components to be used
K25 how to work safely avoiding damage to other vehicle systems, components and units and contact with leakage and hazardous substances


**1.** **Equipment** is

1.1. hand tools
1.2. special workshop tools
1.3. general workshop equipment
1.4. electrical testing equipment

2. Testing methods are:

2.1. visual
2.2. aural
2.3. functional
2.4. measurement

3. Electrical units and components are:**

3.1. lighting systems
3.2. wiper systems
3.3. security and alarm systems
3.4. comfort and convenience systems (including infotainment and communications)
3.5. electric window systems
3.6. monitoring and instrumentation systems
3.7. engine starting systems
3.8. battery charging systems

Scope Performance

Scope Knowledge





This section contains examples and explanations of some of the terms used but does not form part of the standard.

Agreed timescales:
Examples include: manufacturer's recommended work times, job times set by your company or a job time agreed with a customer.

Comfort and convenience systems:
Examples are infotainment and communications, heated seats, electrically adjusted seats, heated screens, electric mirrors, heating, climate control and air conditioning.

Units and components: 
Any unit or component from the electrical systems defined in the Scoping Statement above.

These can be any of the following – light vehicles, commercial vehicles, motorcycles, mopeds and scooters. Additionally, these vehicles may be SI, CI, Hybrid or Alternative fuel vehicles.

Alternative fuel:*
This is defined as any type of fuel that may be used to power an internal combustion engine, examples would include LPG, bio ethanol etc.

Links To Other NOS

External Links

Version Number


Indicative Review Date

31 Mar 2024





Originating Organisation


Original URN


Relevant Occupations

Engineering, Light Vehicle Service Technician (Automotive), Vehicle Trades

SOC Code



Electrical; units; components; remove; replace; light; lighting; alarms; wipers; electrics