Do you have a CCRM (the black box mounted on the overflow bracket)? The wiring harness for it is on the passenger inner fender (about where an aero fox air box is) if you need to hunt for the CCRM. Some folks put it in the fender.
Assuming you have this and want to run new load-side wiring from the CCRM to the fan (double check your wiring diagrams and car in case some goober put the wrong CCRM in the car):
CCRM Pins 1 and 2 go to the low side fan motor terminal.
CCRM pins 6 and 7 go to the high speed fan motor.
Here is some info and diagrams that should be helpful:
click me.
If you have the CCRM and need to test those above-listed pins, you can mmic the tech note about installing manual fan switches. Instead of listening for the fan to come on, put your test light on the appropriate CCRM pins (1,2 or 6,7) and see if the test light illuminates.
EDIT: when you look down at the fan (from the vantage of standing at the front of the car looking down), the top fan terminal is ground, middle is low and bottom is high as I recall.
Otherwise, I'm pretty conversant with the circuits here so post up specifics if more questions remain.
Good luck.
