Dan,
For 12 volts there is no non-contact tester. For 12 volts dc go to Wal-Mart
or the like and get a test probe. That will have an illuminating handle,
wire with alligator clip, and the shape will be like an ice pick.
The Greenlee is exceptionally sensitive beyond the specified range. You can
run it thru your hair, put near any cord or light bulb that is turned on, or
any ac electronic device. It is exceptional to put near the door of your
trailer to "see" anything there that can shock you before touching. It will
also react to spark ignition wires on you car.
-Eddie-
Houston, TX
----- Original Message -----
Home Depot, about $9.99, you will like it. See link below.
http://www.greenlee.com/product/gt-11/start.html