when I did my GSR swap, my ECT switch was bad too...here's the thing, is your electric fan on your radiator come on as soon as you turn the car on, if your fan isn't turning on as soon as you start the car, it can't be ECT?

I know not everyone is as stupid as me but, i mixed up the Power streering switch and the ECT switch...threw code 6. worth a shot to check...