I was looking through my FSM for my 1993 and I came across the wiring diagram for the ASD relay. I know where the relay is at on the truck, but they way the diagram shows how it is wired does not make any sense. Can someone explain this to me please.

 

So I guess everyone else is just as confused as I am

 

I'm not.

The ASD relay supplies power to the alternator field. The PCM powers up the ASD relay when it sees over 400 RPM from the crank sensor.