alternator wiring question

[bizzard]

Ah, thank you. metal then. Galaxyranger needs to get that cable moved out of it and turned half a turn away from it, double quick in case it it cuts through the yellow insulation and dead shorts, if it hasn't already and be the cause of the trouble/

[Tony Brooks]

Have we had a description of what the warning lamp does?

 

Exactly how did the OP test the voltages at the alternator and , more to the point, where was the meter connected.

 

Battery voltage between B+ and the case or a negative is as expected unless the master switch is off or the battery disconnected.

 

Battery voltage between D+ (warning lamp terminal) and negative is not to be expected unless the brushes were worn or the regulator open circuited and the ignition is turned on. Should be all but zero. With the fault stated the warning lamp would not light up  and the alternator would not energise..

 

You will get battery voltage between the terminal on the end of the disconnected warning lamp wire and negative with the ignition on.

 

 

 

 

[Tony Brooks]

21 hours ago, Tony Brooks said:

Have we had a description of what the warning lamp does?

 

Exactly how did the OP test the voltages at the alternator and , more to the point, where was the meter connected.

 

Battery voltage between B+ and the case or a negative is as expected unless the master switch is off or the battery disconnected.

 

Battery voltage between D+ (warning lamp terminal) and negative is not to be expected unless the brushes were worn or the regulator open circuited and the ignition is turned on. Should be all but zero. With the fault stated the warning lamp would not light up  and the alternator would not energise..

 

You will get battery voltage between the terminal on the end of the disconnected warning lamp wire and negative with the ignition on.

To add to the above. I think you can get 12V on the D+ (warning lamp terminal) with the ignition off when a main positive diode fails short circuit so still an alternator fault.

[Sir Nibble]

16 hours ago, Tony Brooks said:

To add to the above. I think you can get 12V on the D+ (warning lamp terminal) with the ignition off when a main positive diode fails short circuit so still an alternator fault.

And that is what it sounds like to me. Hence both batteries collapsing when starter is engaged because the split charge relay is permanently engaged. The black visible behind the B+ terminal is not Paint or tape, it's the insulator.