[btwilson86]

Well, I know on most vehicles windshield washer motors are only on when the key is in the on position (dunno about the supra). You could use a volt meter and test the voltage between the various wires there and a chassis ground to find one that's only powered when the key is on. Using a tap splice you could then run straight to what you need powered, as long as it is just a low amp signal.

If you need to draw current from this line, again use a tap splice and run a wire to the coil side of a relay of proper amperage. Run another wire from the other coil contact to a chassis ground. Then run another wire (with a fuse) from a 12V power source (battery or fuse box) to the contact side of the relay, and then a wire from the remaining contact to the power input on your fan switch. This way you draw very little power on the windshield washer motor circuit, but only allow the fans to work when the key is in the on position.