Automotive Circuit Test Light

Testing Fuses: You don't even have to pull the fuses out of a car's fuse box. You just touch the metal tip to the tiny exposed metal dots on top of each fuse. If it lights up on one side but not the other, the fuse is blown.

Finding a "Switched" Power Source: Perfect for someone trying to install an aftermarket stereo, dashcam, or under-glow lights who needs to find a wire that only turns on when the ignition key is turned.

Diagnosing Dead Components: If a headlight or trailer light isn't working, you use this to trace the wire backward until you find the exact spot where the light stops turning on.