[njsteve]

Figured out the high speed fan problem.

I checked the relay connection and it is the melted wire syndrome. 20 years ago I put an inline fuse in the power feed for the high speed circuit, where it enters the relay. You can actually see the orange wired, white plastic inline fuse holder in the upper left corner by the passenger side hood hinge, in the first photo above. I think I did this because the original wire melted, so I thought a fuse would protect the wire in the future.

In actuality, all it does is heat up the inline fuse carrier enough that it softens the plastic and then the metal connectors no longer contact the inline fuse, cutting off the 12 volts feed.

I jumped the two ends of the melted fuse holder and high speed then functioned perfectly.

I guess I forgot that the relay is the thing that is supposed to be protecting the circuit from heat damage but it doesn't do too good of a job at it.

I guess I will go back to the original 12 gauge wire and forget the fuse.

This seems to be a common problem on the F-bodies.