I just installed a switch to manually operate the hi speed fan so I can help cool off the motor between runs at the track, or Dyno pulls for that matter.
If you race your car this is a very simple but worthwhile modification.
I mouned the lighted rocker switch in my front cup holder next to my line lock controls. Works great.
(I closed the hole so you no longer see the wiring)
Very simple to do like this....
Link to FORD fan wiring diagram PDF file...
http://fiveguysracing.com/SERVICE_MA...ling%20Fan.pdf