Check the Whole Wall Cavity With a Stud Finder
The Tools You Need
Once your hole is drilled, you can shove a glow rod through the hole to start fishing wire, attach your wire to the eyelet at the end and pull it back through. Glow rods can also be used to hook wires to pull them out. As their name suggests, glow rods glow in the dark. This makes them easier to spot when you're working in dark areas fishing wire (which is most of the time).
Glow rods come in various lengths and thicknesses, and you can combine as many sections as the job requires. Thinner rods flex more and work better when you have to make sharp turns when fishing wire. A thicker rod can span longer distances and is better for hooking wires that are more than a few feet away. A 9-ft. glow rod kit costs about $40 at home centers. Expect to pay about $60 for a 24-ft. kit.