Does anyone know the location 1997 Audi A4 Quattro Engine Temperature Sensor? ...and are any special tools needed? Could a little rookie like me change it myself?

I think it's the sensor because when the gauge is all the way to H and the temp icon is blinking, the engine temp and coolant plastic tank thing is actually normal temp - it was 190-194 according to the heat tool thingy I used in several places - Also, sometimes the gauge appears normal...sometimes it doesn't. The oil temp is normal, no coolant is spewing anywhere, the coolant lid doesn't have any overflow or pressure when I unscrew it...nothing under the hood is too hot to touch for 3 seconds...so...I'm thinking it's that sensor...what do you think?

Thankyouverymucho
~Lisa