Non-charging help 89 Dakota

Mine is #321. Bought it new. Wife says sell it. We honeymooned in it. I refuse to sell it. It's too much fun to drive. LOL
The charging circuit was working the day I took the truck apart. I know crap can go bad at any given moment, so who knows. One more thing to look thru, I guess.
Any Idea on the tach function. I believe the diagram shows it coming out of the main board on pin 50. But trying to figure out if I can bypass that and wire it directly?