I’ve probed multiple locations on the body that should give me good ground readings. Including one of the screws holding the dimmer to the floor. The results are the same regardless of location. Im using a “Power Probe” tool. Very nifty little device. Allows you to supply power or ground to any circuit to check wiring or bulbs, like the dash lights for example i can add voltage there to illuminate the whole cluster. Passively you can touch the probe to a wire and it will tell you if its hot or ground like a multimeter.
