Wiring that falls out of its routing on equipment or trailers has a tendency to get torn off. Metal clips work to solve this problem, but another solution is to use silicone caulk. Put a dab where you want the wire to run, then push the wiring into the dab. Tape the wire lightly so it stays put while the silicone cures.
To be certain you’ll have touch up paint you will want to buy a gallon or so extra and be sure to have the salesperson write down the exact ingredients of the paint you choose. Luckily, there are machines available which can analyze a chip of paint but, there’s that old saying about an ounce of prevention…it could save you from buying gallons later.