Well, the pic speaks for itself. I opened the boot to try and fix the back wiper. After the repair of all but 2 of the wires, the dam thing still doesnt work, lol (sigh)

You know, I don't want to replace the whole harness so I tried cutting out the bad areas and soldering/heat shrinking pretty much every wire back together in hopes that the heat shrink has a little more 'play' than the original wire casing. Seriously, I should rip apart my Celica and see how they did their wiring because that car is a 4 years older and has no issues like this. This happened on the two front doors too.

 

That's ugly.

No, the heat shrink won't have more play. It will be more stiff than the original wiring. You're going to add soldered wires, which aren't flexible, and then heat-shrink over that. That's NOT going to be more flexible.

I'd add in an extra few inches, if I had that mess. And I'd use more flexible wire. That's where the problem is - the quality of the original wire.

 

It's not so much the quality as it is the age, stuff gets brittle over time. The best way to deal with that mess is to cut way back in the harness, and replace the wire with an extra inch or two for stress relief. Then find a rubber grommet for the hole that's in the sheet metal to prevent the wire from chaffing, and a little flexible cable conduit will go a long way the help prevent that in the future...