That sounds good but if thats the case why not just run a ground straight to the fan and skip all the wiring diagram hunting and get to the problem quicker.

Also if that doesn't work check the switch you just replaced to see if the correct current is flowing through it. Maybe a wire got switched somewhere in the install or something.

Also make sure the engine is warm enough to need the fan. Alot of 4 bangers hardly turn the fans on at idle. I can leave my car at idle and the fan will never turn on. Rev it up for a bit or drive it around before hand.

Good luck