Combining Multiple Vector Lines that are overlapping in Illustrator


I need to simplify my vector file. The file that was given to me is a vector that has multiple paths overlapped on top of each other.

These drawings are very detailed, and the original software it was created in was for engineers not necessarily meant for graphic designers. I now need to take their drawings and use them in my designs, but the vectors are so complex and unnecessarily overlapped, that it makes Illustrator lag because of the size and complexity of the vector. Is there a way to merge lines that are touching other lines in a quick and simple way, kind of like the function of pathfinder, but for lines.

I've attached photos for examples, but it doesn't get the full visual of the multiple lines that are piled onto of each other.enter image description here

5/19/2018 5:12:00 PM