Is there anything in the fuse blocks in the engine compartment that would be part of that system ?
Here are some more drawings showing the power distribution from the battery to the instrument panel.
2001_impala_battery_dist_CA33LHHX.gif shows three 60A fuses in the top underhood fuse box which feed the dash fuse boxes. One fuse feeds the left instrument panel box and two feed the right. Check those first. But I doubt they are the problem - if one was open, you would probably see lots of other stuff not working.
Next, 2001_impala_AC_fan_CA27G9YN.gif shows a 20A fuse in the left instrument panel fuse box that feeds the HVAC control module. That one should be good since the fan is working on the lower settings.
2001_impala_right_IP_no2_CA49UZYV.gif shows the 25A HVAC BLO fuse which feeds the blower on high. But I think you've checked it already.
These are included for complete-ness, but I don't think there's anything else there which pertains.
I'd say, at this point, you need to probe the orange wire going to pin F of the resistor and see if it has 12V on it when the fan is set on high.