Alternator question., Not Charging. Options

[Olympic 914]

Took the car out for a drive today, planning on going to dinner. everything is working as it should. getting on the PA turnpike and I had to accelerate briskly to get into traffic, and a moment later I noticed that the RED alternator light had come on. Pulled of at a wide spot to check the belt and wires and shut it off. Not checking the belt with it running. Belt good, plug tight, tapped the VR a couple times for good measure and started it back up. Light still on and now my Autometer AFR gauge just had bars. I know that is because it doesn't turn on until the voltage is +13v So not charging.

Now I am on a limited access highway with the next exit `12-15 miles away. Good thing had the battery fully charged on the tender before I left the house. So I made it to the next exit, turned around and headed back home for a total of 35 miles on battery only. Whew. But that shot dinner.....



Replace the VR with another I had that previously tested good. still no charging. checked the plug on the relay plate again. looks good.

I have not yet checked the wire connections at the alternator, possibly a wire vibrated loose during the brisk acceleration.

Now the question

I read to test the VR to short between D+ and DF and if the alternator is good voltage at the battery will go to alternator maximum of about 15-16V

So do I REMOVE the VR for this test? and jump between the D+ and DF at the relay plate.
OR
Leave the VR in place and short between those pins?

[GregAmy]

Yep. All grounds and battery cables replaced by me a couple years ago.

Have not replaced the alternator pigtail though. I wonder if that's accessible with the alternator in the car?

[dangrouche]

Yep. All grounds and battery cables replaced by me a couple years ago.

Have not replaced the alternator pigtail though. I wonder if that's accessible with the alternator in the car?

the pigtail at the alternator end needs the alternator removed, and the metal cover shield removed as well. (IMG:style_emoticons/default/sad.gif)

HERE IS METHOD TO TROUBLESHOOT THE INSTALLED ALTERNATOR:
I did have a complete functional alternator assembly(alternator with the pigtail connected). I attached an alligator clip to the "extra alternator" body and grounded it to the car. I also did the same by connecting the positive terminal of the the external alternator to the car battery terminal. I plugged in the pigtail of the extra alternator onto the relay board. I switched the ignition key to the "on" position. I looked at the idiot light to see whether it glowed or not. (It did not glow with the installed alternator. ) The idiot light DID glow with the extra alternator, which meant installed alternator was failed (diode or brushes).

At least this way, I did not have to go to the trouble of pulling and testing the installed alternator. In the end, I rebuilt the installed alternator for $15 with a pair of alternator brushes from RockAuto.