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142 Guy · Apr 1st, 2021, 15:53

I see 12v is exiting the AMP light by the yellow cable. I measured this by separating the multi connector a few inches away from the AMP light. However, only 1.5v is reaching the voltage regulator. - Are you doing this test with the ignition switch in the run position? If you are measuring 12v on the regulator end of the yellow wire with the yellow wire disconnected from both the alternator and regulator, this would be normal. If you are measuring 1.5v on the regulator end of the yellow wire with the yellow wire disconnected from both the alternator and regulator, this would be a sign of a problem with the yellow wire - likely a short to ground.

I performed one of Pigeon's tests, by disconnecting the green DF cable from the alternator and very briefly directly connecting 12v from the battery, but forgot to put indicator bulb in line &#129402

The voltage reading at the battery immediately went up from 12.5 to 14.7. Does this definitely show that the voltage regulator is not working? - It 'definitively' shows that the alternator appears to be working. By the process of elimination that leaves you with a defective voltage regulator or a problem with the wiring attached to the voltage regulator

HOWEVER, I now have no AMP light. The bulb is fine and I still get 12v exiting the light connector on the yellow cable when measured at the multi connector. HOWEVER, now I get a full 12v where the yellow cable joins the voltage regulator. so.. - If the yellow wire is still connected to the voltage regulator and the alternator, that is a problem. Check that you don't have a bad connection at the voltage regulator, particularly that failed earth connection you found. If all the electrical connections are fine then the voltage regulator is most likely dead.

Apr 1st, 2021, 15:53	#15
142 Guy Master Member Last Online: Apr 27th, 2024 15:46 Join Date: Jul 2020 Location: Saskatchewan, Canada	I see 12v is exiting the AMP light by the yellow cable. I measured this by separating the multi connector a few inches away from the AMP light. However, only 1.5v is reaching the voltage regulator. - Are you doing this test with the ignition switch in the run position? If you are measuring 12v on the regulator end of the yellow wire with the yellow wire disconnected from both the alternator and regulator, this would be normal. If you are measuring 1.5v on the regulator end of the yellow wire with the yellow wire disconnected from both the alternator and regulator, this would be a sign of a problem with the yellow wire - likely a short to ground. I performed one of Pigeon's tests, by disconnecting the green DF cable from the alternator and very briefly directly connecting 12v from the battery, but forgot to put indicator bulb in line &#129402 The voltage reading at the battery immediately went up from 12.5 to 14.7. Does this definitely show that the voltage regulator is not working? - It 'definitively' shows that the alternator appears to be working. By the process of elimination that leaves you with a defective voltage regulator or a problem with the wiring attached to the voltage regulator HOWEVER, I now have no AMP light. The bulb is fine and I still get 12v exiting the light connector on the yellow cable when measured at the multi connector. HOWEVER, now I get a full 12v where the yellow cable joins the voltage regulator. so.. - If the yellow wire is still connected to the voltage regulator and the alternator, that is a problem. Check that you don't have a bad connection at the voltage regulator, particularly that failed earth connection you found. If all the electrical connections are fine then the voltage regulator is most likely dead.