Looks from the picture like it is bearing wall, but need to check the direction of the joists above to be sure. Take down as small a piece of the ceiling next to the wall as possible to see which way they run. If they run perpendicular to the wall then it is a bearing partition.
Modular homes usually have "split" walls like this because they come on different trucks and are put together on site. If the above described investigation finds it to be a bearing wall then you will need to building temporary walls on each side of the exsting wall. About 2'-0" away to give you working room. Ensure that this wall system extends to solid ground. So if you ahve a bsement you will need to build temporary walls at this level and the basement level. you will need to replace the wall with a beam system that is wide enough to catch both structures of the two "mobules". The posts that are at each end of the beam need to also extend to grade and possibly will need footings to carry the load. If you have never been apart of this kind of renovation, it might be worth calling in a professional. It is a very laborious job and if not done correctly, could go very wrong.
