I lost a tail light wire behind my back paneling. What worked best (after several try's) was a long nylon tie or zip tie. Flexible (yet could bend it around)and wrapped gorilla tape around. When real quiet I could hear when it picked up wire and when it fell off. Took several cups of coffee. Was almost going to buy cheap harbor freight flexible camera to check out behind paneling.
Was explaining triumpful moment to my neighbor some time later and he had this handy thing, can't remember real name but this search works for what he had and not to much money.
https://www.google.com/search?q=part+picker+upper+tool&biw=1188&bih=566&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj_p8fYtJnLAhUP8GMKHY1PBEMQ_AUIBygC#tbm=isch&q=flexable+part+picker+upper+tool
