I think that thingy may be a test probe, assuming the brass tip is exposed and not covered with something non conductive. The alligator clip goes to ground and you touch with the tip to find hot terminals. Probably lights up just behind the tip.
It'd help if your photos didn't have everything else in the background.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
