[A1971Blazer]

I replaced the alternator on my LS1 with a 140 amp one...
when I wired the engine to test run it I plugged the single red wire from the harness into the alternator as it should be
ran a #8 wire from the terminal and just left the other end open (protected of course)
I fired the engine and checked the output on the wire...nothing...no voltage output
I then attached the wire directly to the battery I was using to run the engine...Immediately it jumped to 14.25V...(battery was a little weak)
I assume this means that the voltage sensing and control of the alternator by the PCM is working properly?