they are driving me nuts i try to do them but my thumb just mutes the string and if i do get a harmonics it is VERY low
help?

Its just takes a little bit of experimenting. Try notes on the Low E string then work your way up to other strings.

You need to test the pinch along the string between the 2 pickups. You will eventually hear where it's strongest, and generally I have about a 2mm gap between the pick and my thumb when I do it, but you'll kinda adopt your own position when you find it.

Youtube vids , go to ultimate-guitar.com and search the lessons.

Also its a lot easier with bridge pick-up.

What he said.

i have a statrocaster type with the 3 pickups

OK. (?)

i mean wheres the best spot on those to hit a good ph

Mainly any fret and string. It gets easier when you go with high notes but basically any note can amke a pinch harmonic