José Feliciano was asked to write a theme song. He was worried that the producers would reject his song, so he wrote two. The producers bought both of them and used one at the beginning and the other at the end.
The series was originally developed for Cheech Marin and Tommy Chong. Creator James Komack followed the comedy duo on their tour and wrote a script based on their act. Cheech and Chong turned it down because they preferred to work on feature films. Komack changed the character written for Chong from a young Asian-American to an elderly Anglo-American.
Freddie Prinze committed suicide after rising to stardom as Chico, forcing the producers to bring in new cast members to replace him. The replacements were not accepted and the series was cancelled soon after.
During the first year, Chico used the catch phrase "That's not my job", which Freddie Prinze had used in his stand up act. Some people complained this perpetuated the image of the lazy Hispanic, so he switched to the catchphrase "Looking Good".
When the show returned after Freddie Prinze's death, Chico's absence was explained by having him quit the garage to work for his father. However, later that season it was revealed that Chico died.