Here's a thread on how someone bypassed (actually bridged) the low speed circuit. Ignore the comments about how current (amps) will be increased. It won't. I have 2 master electrician licenses, so I know electricity. The fans will pull the same current on low or high speed, voltage is reduced (and thereby fan speed) but current will remain the same. It would stand to reason that you wouldn't be pulling more than you would on high speed since the fans have only one winding. It would be nice if Ford were to give us multiple winding fan motors instead of resistive circuits, but that would be much more expensive, and larger.
Solution to cooling fan resister failure???