Thanks for all the feedback. I researched a little more and agree that most of the OEM fans are two speed.
Wire gage in the current low speed circuit would be important. I didn't realize that low speed had it's own fuse. I'll check that out and verify juice to the plug. I was thinking that when I pulled the resister out, it would be fried. Time for the VOM. And clean connectors.
Seems like wearing out the motor would be the biggest negative.