I use a little piece of pex w wire in it....pretty easy, you don't have to drill,Thanks everyone. Ended up pushing a clothes hanger (more force than I imagined) from inside cab to out, taping the wire on and pulling it back in. It just took more force than I really imagined.
any chance two zero gauge wires with nylon sheathing would fit through that?I heated an ice pick, and pushed it through. No cutting, no sharp edges . Then fished wire through when installing trailer tow harness (flat four) power wire