You will be able to see Datacrons from quite a distance as they emit a large glow around them and shoot a beam of light into the sky. If you are very close to a Datacron you will also be able to hear the sound from them.
Datacron Locations By Planet
Balmorra – 5 Datacrons
Purple: Willpower +4
Location: -779, 2069
Start at Coordinates -651, 1831. Jump onto and follow the pipe until you connect with a dirt road. There you hug the wall as you follow that road looking over to the left until you see the Datacron below and drop down onto it.
Green: Endurance +3
Location: -432, -293
Inside the Colicoid Queen’s Nest head toward to coordinates -358,-232 and you will see a small tunnel entrance. Follow it, killing the enemies inside. Eventually you will reach the Datacron.
Yellow: Cunning +4 (Unlocks Galactic History Entry #23)
Location: -1017, 1516
Head to the Okara Droid Factory -1060, 1486. Go to the lift that takes you to the assembly line -1150, 1612. Once there, you will drop down into the assembly line and go to Coordinates -1020, 1520. There you may want to turn your walking on (The “/” key on your number pad) and drop down the pipes eventually landing on your Datacron.
White: Aim +4
Location: 190, -342
In Bugtown South take the ramp down to the lake and head east towards a small ship in the distance. There is a Junk Dealer at coordinates 672, 36. Purchase the Lost Code Cylinder from the Junk Dealer and head to coordinates 190, -342. Open up the locked box to claim your Datacron.
Yellow: Presence +4
Location: 729, 2029
Start out at the Lower Sundari Outpost. Head to the bridge at coordinates 780, 1559, cross it. Once you cross over the bridge carefully make your way to the Big Satellite Dish at Coordinates 676, 1845. Behind it you can see a small path which you must follow. The path will take you to an area with some elites and a mini-boss guarding the Datacron. These guys can be easily avoided by hugging the wall or climbing over the rocks.