Congrats--good going!

Glad to hear you got it working. The ECU does control the fan operation by grounding that pin you tested and the temperature sensor used to monitor the coolant is the one used by the ECU, not the dash gauge. By manually grounding the pin you proved that the fan operation was good to that point of the circuit but the ECU wasn't doing its' job. The switch driver inside the ECU had most likely failed and caused the issue. You got a good price on the replacement ECU. 

Thanks for your help Cougar (and everyone else!).  I've replaced a few things before like starter, alt., axles, etc. but never got into anything electrical.

I was always pretty intimidated by that.  But when you look at the schematics and wiring diagrams, it's starting to seam a little less confusing.

It's so great that folks on this forum are willing to take the time to help. I always feel great when I fix something my self and think about the money I saved!

The wiring prints take a little getting used to but once you figure things out you will see how fairly simple most circuits are designed. You won't want to work without the drawings as they save you so much time. Having the drawings and knowing how to work with a meter will pin down problems in short order. Good job.