I am trying to finally wire in my isolator after a few years of having it just sitting in my engine bay.

I have everything wired up (correctly i might add, i checked it many times) and fired the car up and the alternator wont put out a voltage.

Before this it has always had a slightly low output and would dim with turn signals and such things but it would run fine. There is a sense wire that i hooked up to the alternator and the isolator output to compensate for voltage drop from the diodes. It doesnt make a difference whether that is connected or disconnected and it seems that the PCM is only putting about half a volt to the L wire on the alternator and best as i can tell, it should be +12.

Why would it WORK before the isolator and NOT after? the physical electric properties are the same, does the diode drop the battery voltage enough to cause the PCM to not send full voltage to the L pin on the alternator?