You can see this Red Datacron while exploring in Shadow Town, behind a grate in a pool of sewage water, but you’ll need to find a different way to reach this datacron.
If you’re looking just for the boost to your stats and the Galactic History 37: Freedon Nadd codex entry from the Red Datacron on Nar Shaddaa, the Imperial version of this red datacron is much easier to get, and both the stats boost and the codex entry seem to be shared.
Quick Travel / Taxi
The Republic [HEROIC 2+] Breaking Down Shadow Town is very close to the datacron, so instead of quick travel or taxi, picks up the Heroic and it will save you a long run.
Travel Deep into Shadow Town
Find the Crates
There is a large pile of crates hidden inside a caged area in the south west section of Shadow Town.
Jump up the crates until you get to a large caged walkway.
Follow the walkway until you see a bridge and cross it.
Across the bridge, you will actually see a blue datacron that is slightly different than the normal datacrons. This is called a “light vs dark datacron” and was part of a now-retired event.
You can click this datacron if you want, but to get to the one that we are looking for, you will keep moving past it onto some crates you will use to jump onto some pipes.
These pipes are the main jumping puzzle. Jump up from the crates onto the first pipe, then follow the pipe carefully. Halway through the long pipe, there will be a l-shaped bent pipe on the wall you can jump up to to continue moving forward and upwards.
From the l-shaped pipe, jump onto a glowing lamp, and from the lamp, jump up on to a slanted ledge up above that has a red glowing strip light on it.
From the ledge, jump onto the zig-zag shaped pipe. From there the path will fork to the left or the right, you’ll want to go left where you can see a bunch of stuff to jump onto.
There are two pipes on the wall you will need to jump between. This is the one I often get stuck at. I found if I back up on the first pipe, and try to jump on the second pipe’s circle, coming at it diagonally, I have the best luck.
Once you are at the end of the jumping puzzle, you can jump up onto the big ledge and there will be an elevator you can take. Once up the elevator, the datacron will be sitting in a pool of technicolor water.