I have the earlier version of the power probe and it's the #3 ranked tool, after the Snap-on tester that uses hot & ground by means of alligator clips or cig outlet. I only use the Power Probe when I need to introduce 12vdc + or - for testing. Other than that, the primary tool for diagnostics has always been this tool:
http://www.amazon.com/gp/product/B000I12RUW
- It is computer safe - meaning I can probe without fear of damaging any delicate circuits, even around airbags if they are not clearly marked by the telltale yellow jacket. The Power probe is circuit safe ONLY if the + or - button doesn't get pressed!
- It is hands free - no wires! You simply touch any portion of the chassis ground. Most of the time, I'm already touching ground through my body without intentionally touching ground with my free hand.
- It's quick - faster to use. It's ready to work the minute you pick it up.
- Dual indicators - light & buzz
- Dual voltage - Detects up to 28vdc. A plus when working on 24vdc systems.
This tool ranks in the top ten tools in my toolbox and as a warning, no one should use these 3 testing tools without a basic understanding of electrical theory. All it does is detect the presence of 12vdc that is LOOKING for ground. For instance, I use this tool to locate ground switching horn ring. I probe a wire that I suspect is part of the horn ring circuit. If it's the correct wire, it will show positive when the horn is NOT pressed, nothing when the horn is pressed. If you are nodding in agreement, this tool is for you, if you're not, call a professional.
As any reputable installer will tell you, never, ever use the generic tester with that 12vdc bulb in the handle. I see young installers come in with it and I tell them to crush it and throw it away and I give them $2 credit for them to use it on a quality tester.