When you need to test wires in a wiring harness, it is often helpful to be able to probe the wires individually while everything is still connected together. The best way to do this is to probe each wire with a pin - service manuals will often even advise this technique. Up until now, I have been literally doing just that - pushing a straight pin into the wire. This is not the safest or most convenient manner of doing this, though. You can accidentally short something out. You can get stuck with the pin (ask me how I know). Or maybe you just don't have any straight pins laying around.

Enter my Probing Pliers. Simply connect the lead to your meter; lay the wire you need to probe in the gap; and squeeze.

To assemble this, you will need a single strand of CAT-5 with the insulation stripped; a push pin; and a length of 24 gauge hookup wire.

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Assembly

• Break the plastic off the push pin and snip the upper end (opposite the point) off to remove whatever means held it in the plastic.
• Using a pen drill, drill the upper hole in the jaw to the size of the push pin.
• Using a small hobby file, round the end of the CAT-5 wire (otherwise it will get stuck in the next step - trust me).
• Feed the CAT-5 wire through the lower hole in the jaw back down towards the handle.
• Solder the hookup wire to the CAT-5 cable.
• Pull the CAT-5 wire (and by extension, the hookup wire) back through the pliers as far as it will easily go.
• Wrap the CAT-5 wire around the push pin about 5mm or so from the pliers and solder it in place, holding on to the wire with a heatsink (pliers, forceps, alligator clip, etc...) to prevent heat from creeping back up the wire and melting the plastic.
• Push the pin into the hole you drilled out earlier, securing it with either epoxy or super glue.
• Pull the hookup wire back out enough to take up any slack in the CAT-5 wire.
• Trim the hookup wire to whatever length you want and attach an alligator clip.
• Finally, using your adhesive of choice (I prefer https://www.amazon.com/gp/product/B003HNFLMY for PLA), glue the two halves of the bushing together through the pivot point in the pliers, keeping pressure on the bushing until the adhesive has fully cured/dried/set to ensure a snug fit amongst the pieces.

Voila. Probing Pliers.