Loctite (TM) makes some stuff (part no. 15067) to repair breaks in
the defroster wires. It's a coppery looking goo (yes, it's
conductive) that comes in a tiny 'fingernail polish' type dispensor. 
It works.  Finding the break in the conductive strip takes the sharp
eyes of a nine year old, if you can't remember just how the
ice-scraper hit the rear window when you winged it back there from
the front seat!

Actually, you can 'find' the break by tracing the non-heating element 
over with an ohm-meter until you locate the break in the conductive 
strip.

BTW, I had to buy that metal pipe on the left side of the engine that 
routes the big dia. coolant hoses around and has a heater hose on it 
(diagram part #24 on the fiche) as mine cracked at the heater hose 
junction and puked out all my antifreeze in a hurry.  Dealer cost 
~$49, my cost $81...  just thought I'd add 'nother 'possum to the 
stew :)

-dan new '87 Westy down for the count...
          old '85 Weekender ignored, sullen, and running just fine 
for spite