Charging system not working..?

[GODofWARREN]

Alright so I tested my alternator after my car died after loosing power to all accessories. The battery checks out fine as did the alternator when i had it tested 3 times at Autozone, and 3 times at Advance Auto. I found a youtube video with a bunch of tests to see what could be going on. One thing I did discover is that with a volt meter you can test the negative side of the alternator by turning the car on and touching a volt meter on the positive battery terminal, and the negative on the shell of the alternator. its supposed to read -.1 to -.2, well mine read -11... So i have a bad ground somewhere and where im at now, is the ground in the alternators charging system, or a ground in the engine bay somewhere? I checked the battery ground and the ground on the top of the intake manifold. the only one i havnt been able to check yet is the one on the block due to work.
Was wondering if anybody has ever dealt with similar issues and it turned out to be the alternator..? Or could point me in a ground that may be known for going bad..?

 

[Spanky_DSM]

Theres another similar thread floating around right now..

check your 100amp fuse crossing the alternator to the battery in the engine bay fuse box

 

[DSM1G90]

Take the VOM, put it on DCV, with the car on idle, touch the positive lead on the plus battery post and the negative lead the negative post.

You should be getting between 13.8-14.5VDC coming out of the alternator. Any other readings is a toasted alternator due to a bad regulator.

How good are your cables - do they look all ratty and snarly looking with bad connectors? Connections from battery to ground needs to be metal bright and tight due to the high amperage that flows from battery to ground (did you know that DC current runs from negative to positive?? politics made the change to go positive to negative..) and why its super important to have all connections clean and tight.

 

[GODofWARREN]

I just checked the 100 amp fuse in the fuse box, it appears to be alright, the copper ribbon inside looks clean and is together, and both wires running to it are tight. Ill go check the battery with the voltmeter now.

Put the volt meter on DCV, and the red positive tip on the positive battery post, and the negative tip on the negative battery post, and got a reading of 12.51v...assuming this means its a toasted alternator regulator..?

 

[luv2rallye]

Another thing to check is the dash charge light. It must be working (not burned out or bad connection) to provide voltage to the alt's field coil or the alt will never turn on. There is also an "alternator relay" which is in parallel to the light as a backup but many of these become broken, missing, or burned out.