Can you please tell me how to test an alternator? Thanks ...

Can you please tell me how to test an alternator? Thanks nigel Mechanic's Assistant: Let me get you an Expert to help with that. Before I do, are there any other [details](/topics-detail/) you'd like me to pass on? Not re...

Can you please tell me how to test an alternator? Thanks nigel Mechanic's Assistant: Let me get you an Expert to help with that. Before I do, are there any other [details](/topics-detail/) you'd like me to pass on? Not really thanks

Automotive Expert
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Automotive Expert
Hello again Nigel .il just type out the guide for testing alternator output il be a few mins

Thanks a lot kevin
Automotive Expert
Ok so with the alternator we are testing the voltage output .the voltage output we actually test at the battery .its a good idea to test the battery voltage before starting to rule any battery issues out .so red lead on voltmeter to positive terminal and black lead to negative terminal ,again set to volts .the battery should read around 12 volts .we then need to get a friend to start the engine leaving our voltmeter attached to the battery in the way described .once the engine is started we would expect to see the voltage reading rise to between 13.5 volts and 14.5 volts as the alternator begins charging the battery .we then want to get our friend to turn the headlights on to put some load on the system and we want to make sure the charging voltage doesn't drop below our 13.5 volt reading .it may drop for a second or two when the lights are turned on but as long as it returns the alternator is working well

Thank you very much again kevin , you gave me great explanation

Hi kevin i have an other question please
Automotive Expert
You need to open questions on different subjects up as new requests .you can ask for me

Using a multimeter, how you can rectify a fault, when you have a bulb damage ?How you can determine thay bulb is at fault ?
Automotive Expert
So this is difficult because the bulb completes the circuit.are you referring to a headlight bulb ?

a headlight bulb
Automotive Expert
Ok so to be honest the first step would always be to fit another bulb .the most common issue is that when the bulb is fitted somebody touched the glass section and this will lead to the bulb burning

that's the first thing to do, check the bulb, yes
Automotive Expert
Replace it and see if the issue occurrs again but ensure that when replacing your skin does not contact the glass

what about how to use the multimeter to find the problem please?
Automotive Expert
Its very difficult to trace this type of issue .typically we would carry out an amps test to see current draw by attaching the multimeter inline on the negative side of the circuit.but this isn't always accurate .we need to ensure that the voltage into the headlight isn't above 14 .5 volts by connecting in place of the bulb .each wire on the voltmeter to each pin in wiring where it connects to headlamp with car started

I am afraid i want understand you on the phone, here in Malta its very far away. But i completely understand you kevin. ��Can you at least tell me what can i write to find it on you tube in shortThank you very much for you patience kevin
Automotive Expert
This is a good video for voltmeter basics [](

Thanks kevin
Automotive Expert
You are very welcome .Thanks for choosing just answer today and please let me know if you have any further questions at all . To contact me again for any future questions use the link provided [](//

Automotive Expert
No problem

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