The Nissan Path

I'm looking for a switched power source (activates when ignition is on) in the engine bay to power a cooling fan on external transmission cooler. What would be a good wire to tap into? Thanks!

I used the remote wire from my radio to power the relay for my KC lights. That is inside the cabin though. The headlights might have a lead that is always Hot when the ignition is on, but without checking it with a voltmeter I would have no idea.

Ok, I found a nice spot tapping into one of the empty relay spots in the smaller fuse box, located on the pass side of the engine bay. It the smaller box, located just in front of the second larger fuse box. Actually I'd call them relay boxes, since they house numerous relays. Well, the smaller, front box had a number of relays and one of the spots is empty (towing harness relay). It has both switched ON and constant ON and can be tapped into using any regular flat male connector.