I tried that at first, but the weird thing about these indicators is that there are two projections through two holes in the hood. One for the mounting stud and one for the knurled connection for the signal wire. But the mounting stud is not electrically connected to the knurled barrel where the wire mounts. This barrel seems to be the only place that the ground is needed in order to work. So a star washer under the mounting stud doesn't do the trick.
