Johnny Cash was very popular in the 70's. I'm a bit surprised he played a character that was interested in under aged girls ( Mary Anne and the student he was giving lessons to )

"I Saw the Light" was a song made famous by Country Western Legend Hank Williams, I believe in the 1940s or 50s.

Bruce,

You made me look!

Looks like it was written by Hank W. upon awaking from a drunken stupor.

"His mother, Lilly, drove him and the band back to Montgomery that night. As she was approaching the city, she spotted the lights of Dannelly Field Airport. Williams, who slept inebriated in the backseat of the car, was roused by his mother, who told him "I just saw the light", announcing to him that they were close to Montgomery."

https://en.wikipedia.org/wiki/I_Saw_the_Light_(Hank_Williams_song)

A bit of a Colombo connection...the first Hank Williams biopic starred a very young George Hamilton.