Hi! After replacing the whole engine, transmission and brake system (tons of work, but the car runs like new), we had a check engine light for a 41 code, which is alternator is not following PCM voltage controller orders.

After a couple tries, I figure that if I jump from the A142 connector of the alternator to the positive post of the battery, the car runs fine and no errors, battery runs between 13.8 and 14.5 (I live in the mountains where is cold, about 50F).

While I suppose that is a wire broken somewhere, I can't understand the diagrams to find where. I'm kinda stuck. Also, I'm not even sure if I can just patch a new cable, or if by doing that I'm bypassing a fuse link that should not be bypassed.

With the jumper, the gen drive reads 0.7V .
Without the jumper, the A142 reads almost nothing, 0.01V.

 

Welcome to DF
You could have broken fuseable link. All the fuseable links are located next to the washer bottle. remove the washer bottle and pull on each link.