If you want to do it right....and remove the old wire, separate the headliner from the side and back and put the new wire in the clips. I not, fish it in with a small cable or wiring snake. It's really up to you.
"Pay attention to the details! It ALWAYS pays off."
1949 Chevrolet 3100 Series 1/2 ton Pickup 1964 Chevrolet C10 (Ol' Yella) (SOLD) 1958 Chevrolet Biscayne 2 door (SOLD) 1970 VW Beetle