[Peter Serio]

Factory grounds were overlapping thin pieces of steel.

When the car gets old 2 things can happen to these grounds. One is that the metal starts to rust &/or corrode. And the other is the plastic mounts that hold threads which in turn hold the screws which hold the metal strips tight up against one another can crack or break off the back of the dash pad carrier.

Some times the threads in the plastic get weak, that or the threads are stripped out from over-tightening. The wiper switch uses one of it's "mounting tabs" that one of the ground strap end overlaps. That one plastic mount right beside the wiper switch in the dash pad has to be in good shape so that the ground is nice and tight.