where in the passenger side head is the fan switch temp sensor (i dont know the official name)

 

The fan switch has a "mushroom-style" connector. It's higher up than the knock sensor (which has a similar looking connector). I'm gonna go out on a limb here and guess that it was in the region between plugs #4 and #6, but that might not be exactly correct. It's not too hard to find tho, esp if you have headers

 

If I remember right it is just behind and below 6...kinda high up on the block

 

If you have a v8 it is between cly. 6 and 8. If you jack up your can and get under it look up above the starter you will see it on the head right below the heat shield for the exhaust manifold. Getting it out is a whole new trick, I haven’t figured this out yet. Mine was bad when I got the car last fall and I never had a heat problem until last weekend. So yesterday I spent several hours beating on things with no luck. I might just end up a putting in a switch.

 

I feel your pain I spent a good while looking for that crap. i saw it last night when I was under the car. I'm doing a header swap this coming week. I Found it and felt relieved, but then i kinda realized how hard its gonna be to take it off. BTW the headers are cool!

 

ok i found it. it has no connetor on it at all and i am pretty sure i found the connector that is supposesed to be on it. only thing is that is was hanging by the y-pipe and the end is burned to a crisp. i have noticed that my fan is on right after i start my car and the engine is only like 100*. is this why? also if a mod could move this to the electronics forum. thanks

 

I know it's early in the year (tho maybe not in TX) one possible reason for the fan coming on b/f 2xx degrees would be having your A/C selected on your heater/A/C controls in the car...

You can buy a replacement connector from GM for like $15.