Hilton

I wouldn't solder this - there are plenty of types of conductive pen out there. A quick google for "flexible conductive pen" brings up a bunch of stuff - here's one:

http://www.chemtronics.com/products/...r=3&m=2&id=508

Conductive pens are pretty commonplace - used for re-joining laser-cut traces on computer processors, circuit boards etc.

Maleficio

I wonder if ground-loop hum could play into car electronics?

Rick Carter

I bought a new printed circuit for my 85 while they're still available and have it unfolded in storage.