SOT: need EE advice on repairing a BMW wiring short

[area53 at validpath.com (Jeff Toomasson)]

Hi folks - I'm in pretty dire need of some electrical wiring advice. All of a 
sudden over the last few days, the parking brake sensor on my M5 started going 
off while the brake was obviously off. It activated mainly when lurching from 
stand-still. I had the car detailed Monday afternoon and can't remember it was 
doing before although I'm pretty sure it was. 

On top of that, my windows switch started acting up this afternoon - the 
driver front window switch first lowered the back window, then it wouldn't 
work at all. A little later it worked again briefly then stopped. This is all 
after driving in slow-ish traffic in ~95'F weather. This intermittent 
operation has persisted and I ended up just disconnecting the switch cluster 
altogether. Well, I found the damaged wires, see pic:

http://area53.validpath.com/pics/M5/windowshort.jpg

The damage to the wires runs from the paring brake area all the way to the 
wiring trunk at the back vertical part of the floor pan. They are very stiff 
and cooked. There are even some burn marks on the underside of the carpet...  :
(  I'm pretty sure the short is local to that area (as opposed to one of the 
window motors) for two reasons - 1) the damage is localized and 2) and 
according to my mechanic, the window motors are actually on a ciruit breaker 
(as opposed to fuses) which would explain the intermittent operation.

My hope is that I can get another section of wiring from another 5 series and 
splice it in ahead of where the wiring damage starts. Otherwise, I would have 
to completely replace the wiring harness which goes to all four doors. Of 
course, that entails removing the seats, the carpet and all four door panels. 
yuck...

Anyone see any issues with just splicing a replacement switch cluster with 
wiring into the good section?

Thanks, JT (with a probable heat stroke after working in a black car for two 
hours in > 90'F)