81 300 SD power seat wiring

[Old Dies]

Been a long time since I last posted, but I thank you all in advance for your time.
I have a 1981 300SD. Over the years the power seats have slowly lost most of the power functions. Now I am reduced the last setting, the exception being that I am still able to get both seats to slide forward and back. Nothing else works at all.
I know the problem is the power wires have all broken internally where they feed across the door opening. Not hard to believe with a 30 year old car.
Question is what way to rewire those two harnesses. Should I just chop them off and pull them through the frame and the small holes in the door jamb and the door? Is there any easier way? Would it be better to pull the wires out individually?
All suggestions are welcome.

[Whiskeydan]

I would cut and resection each wire one at a time. Easier to feed thru and no chance in wiring error.

Are you sure it's not the switch? The wire used on these cars is pretty good stuff. I've never seen that happen but, have replaced a few switches.