v70 Rear Window Defogger - Not a "broken etch"

[packetfire]

My 2004 v70 stopped defrosting the rear window efficiently. Only the 2nd etch from the top would heat up, which eventually got the ice melted. Very eventually.

Looking at the inner surface with the plastic trim removed, I see that there are two distinct circuits - the topmost two etches are on one "circuit", and the bottom ones are on another. The wide etches at the far edges of the glass, hidden from view, join at the push-on terminals at each side. So the very topmost etch must have a break somewhere.

The design here is pretty clear - all the etches across the glass are of equal width, so the etches are all certainly "in parallel", but the two at the top are deliberately wired "as a group of two", and are connected by a separate wide etch to the push-on terminals. Not sure, but does the smaller mass of metal in these two topmost etches imply that they will heat up first, before the main group below?

(Also the bottom two etches have no ability to heat up, they are the "broken glass detection" circuit for the alarm system, and are served by the smaller push-on connector on the (USA) driver's side, connected to the same ground terminal on the (USA) passenger side.)

So, my strategy is to clean and steel-wool an area of the wide etch, and paint some conductive paint or solder to jumper the two together, rather than tying to remove the (presumably corroded) push-on terminal, and perhaps break the etch even more seriously.

Has anyone else run into this scenario?