I'm new to the forum and not sure how this all works, but here goes... I have a 1999 Infiniti I30 I inherited a while back. The battery died a couple of days ago. Took it to Autozone and got a new one. Clerk told me I could check if alternator was working by running car and disconnecting + terminal. I did and car immediately shut off. So I assume alternator is bad. Went back to AZ and bought a new one (Duralast gold - below). Son and I installed that. Car started and ran fine. I then randomly disconnected + cable again, and again the car immediately died. Not good - alternator should be running the car? I took to AZ again for testing and the unit said alternator "failed". So now I'm trying to figure if I have a brand new BAD alternator (not remanu) or if I messed up the install. I feel like I got all the parts and pieces back where they should be - with the exception of a wire that connects to a bolt on the front of the alternator. It came with a black plastic piece on it and 2 nuts. I first placed the connecting wire between the 2 nuts. So when i put together it was <alternator> <black plastic piece> <nut 1(13mm)> <wire> <nut 2(12mm)>. I tested again the car died again. I then removed the plastic piece and set it up as <alternator> <wire> <nut 2(12mm)>. Tested again, and car died again. Is there a possibility I need to put the wire on another way? Or anything else I can troubleshoot? I can't seem to find the fuse. Thoughts? Though I have working on it, I know almost nothing about cars - so please excuse my lack of technical terms or any real understanding. Below is a pic of the alternator with the bolt in upper left corner. ANY help would be greatly appreciated.

 

The disconnecting battery terminal test isn't a good test for alternator health, you need to buy a cheap $10-$20 DVOM or borrow one and put it on Voltmeter setting and see what it's charging at idle, it should be around 13.5-14.5V at idle. If it's 12.2 or something like that, the alternator likely isn't charging but cross that bridge after you get an accurate voltage reading

 

Thanks for that! I have a buddy bringing one over now.

 

Pretty sure I got a bad new alternator. The battery, car not running, tested at 12.5. When the car was running, it dropped to 12.1. I also tested the post coming out of the alternator where the wire connects and it tested at 0.4 volts. Wouldn't that mean that I have virtually no power coming out of the alternator?

 

It does happen from time to time to get a bad "new" alternator. Watch these videos and determine if your new alternator is truly bad