UPDATE 12/24/17: I did more diagnostic tests . . . Made some progress but still not working. When I put the OEM modded climate control head back it, the fan speed works perfectly now. So I believe that the erratic fan problem that most Crossfires eventually experience seems to be more related to loose contacts within the climate control head than to the resistor on the blower fan. THANKS to the original poster for the write up on this DIY fix here and THANKS to Dave (onehundred80) for making the PDF:

CLICK

I tested the connection to the heater control valves and I confirmed NO POWER is getting to the three prong connector (the #2 female pin on the connector is not receiving power signal from that circuit). I verified my tests on the other two working cars just to be sure my test was being done correctly. Accordingly it would not seem to be a ground issue but rather the test points to some problem with the power in the fuse #15 circuit. So on this image provided by George, it shows the #2 center pin as "fused B(+). What does that mean? Might there be an inline fuse besides the 5A #15 fuse?

Also, the REST pump also runs / gets power from that #15 fused circuit. Where can I find / check that pump to see if it's running / getting power from the circuit?

Any new thoughts??

Thanks again for sharing your expertise . . .
Bob Davis (Red Dog)