Desperately need your knowledge!!

[p-nut95]

I have no idea what gauge strings im using, but i do know that they aren't a very light gauge or a very heavy gauge. But heres my problem, on the E string when i go past the 12th fret the pitch of the note goes out of tune. this isnt because my string is out of tune. I was wondering if it is because my string is too big and it not getting pressed down enough to get the definition of the note or if is how my bridge is setup or what. Will a lighter gauge string help this problem?

[Nighttrain1127]

It is the intonation of that string. Play the E string with the bass hooked to a tuner make sure the vol and tone controls are wide open. Check the E string at the 12 th fret . If it is flat move the saddle towards the neck with a screwdriver turn the screw that goes through the saddle and moves it towards the bridge if it is sharp turn the screw the other way After you turn the screw no more than half a turn retune the string and try it again if it went from sharp to flat or the other way around turn the screw back a bit if not keep going but keep retuning after every half turn of the screw Or you will throw your self off By not being in tune.