Technical Alternator Failure

[SpitefulGOD]

Hi guys, my alternator fail light has just lit up and power steering has stopped working... I want to check whether or not the alternator has failed or if its a connection fault. Not knowing much about alternators I could do with verifying where to check the voltage and what the voltage should be when running on idle....

The belt is spinning although I'm only getting 11.7 volts on the battery, i've managed to get to the alternator but i'm not sure which connectors which or whether i'm checking on the right place... Attached is a picture of the alternator, do any of you guys know which connectors which?

 

[Davren]

The thicker of the 2 cables is the alternator output.

 

[SpitefulGOD]

So I thinks that's B, where would I put the negative connector on the mulimeter? On the frame? Also what voltage should I be getting? Thanks for the help btw

 

[Davren]

Yes it's the "B" terminal.

Connect the -ve multimeter lead to a clean metal part of the engine or the alternator mounting. Set the meter to the 20v scale if it's not an autoranging meter.

With the engine running at about 1500 - 2000 rpm, the alternator output should be between 13.7 and 14.3 volts.

 

[SpitefulGOD]

At the moment i'm manually charging the battery so it doesn't go flat, I'll check the voltage from the alternator in the morning and see what it says. Thanks for your help by the way.