1998 2.0 overheating

[LostJeeper]

Hello all,
I have been having issues with a 1998 2.0 gas bug. Its my wifes car that I have now got stuck with repairing and maintaining. I don't know much about the car (or VW's for that matter) other than the water pump was replaced a few years ago. It also has a sweet oil leak...but thats a whole other problem.
Beyond that this is whats happening and what I have done.
Problem: Car overheats after a few minutes, fans do not come on. BUT the fans do come on if you turn the AC on.
1)I have checked the little fuse block over the battery. I have a little power probe and I touched in all the fuse holes and they are getting power. Fuse itself does not appear to be blown.
2)"The guy" at autozone told me it sounded like I needed to replace a sensor and sold me on that screws into the bottom of the radiator.
3)Added more coolant
4)In the process of replacing the thermostat...the water pump impeller seems to be intact but I cant really see it...just kinda touched it with my finger and I dont know what I'm feeling for.

Ok, at this point the sensor did not change anything and neither did adding more coolant.
Im waiting to put the new thermostat in until I hear what you guys think and until I can double check this water pump. Sorry if these are noob questions or if im missing something painfully obvious.
Thanks for any help and trouble shooting ideas.

[LostJeeper]

Bump for help!

[VWBugman00]

So it may be another sensor. There is a green sensor on the top radiator hose. It's held in place by a U shaped clip. It may not be working right. Good news is, they're very easy to replace, and pretty cheap. I doubt it's the thermostat, but that was a good place to start. As long as that water pump didn't move when you stuck your fingers in there, and isn't in pieces, it should be good to go.

[LostJeeper]

Thanks for the help man! That is one I had thought about replacing but the parts guy talked me out of it. Ill give it a shot and see whats happens. BTW your car sounds pretty sweet (judging by your sig)

[VWBugman00]

Not a problem. And thanks, my car is a lot of fun With my turbo, it's not near it's potential, but that'll be down the road. It's a 300whp car, and that was my goal.