Non-powered test lamps are very useful to determine a live part of a circuit. The objective of this procedure is to show you how to use a non-powered test light.
Part 1. Preparation and safety
- Use a non-powered test light.
Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:
- Work clothing - such as coveralls and steel-capped footwear
- Eye protection - such as safety glasses and face masks
- Ear protection - such as earmuffs and earplugs
- Hand protection - such as rubber gloves and barrier cream
- Respiratory equipment - such as face masks and valved respirators
If you are not certain what is appropriate or required, ask your supervisor.
- Make sure the hood stay rod is secure.
- Always make sure that you wear the appropriate personal protection equipment before starting the job. It is very easy to hurt yourself even when the most exhaustive protection measures are taken.
- Always make sure that your work area/environment is as safe as you can make it. Do not use damaged, broken or worn out workshop equipment.
- Always follow any manufacturer's personal safety instructions to prevent damage to the vehicle you are servicing.
- Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.
Points to note
- Non-powered test lamps are very useful to determine a live part of a circuit. However, make sure that the circuit you are testing does not carry more voltage than the light in the test lamp can handle, otherwise damage could result.
Part 2: Step-by-step instruction
- Verify the test light is operational
Connect the end of the light with the clip on it to the battery negative terminal. Touch the probe end of the test light to the battery positive terminal and the light should come on.
- Connect to known good ground
Connect the clip to any known good ground close to the area to be tested. A typical known good ground is any unpainted metal surface on the vehicle that is directly attached to the battery ground return system.
- Check a circuit
Locate the device to be tested and place the probe so that the test light circuit is in parallel to it. If there is voltage present the light will come on.