Between 1970 and 1992 Ray Charles guested
- 17 February 1970. Among the guests: Ray Charles. Unknown content.
- 30 May 1972. Guests: Ray Charles, Maureen Stapleton. Unknown content.
- 20 April 1973. Guests: Ray Charles, Cliff Robertson, John Davidson, The East Trucking Company and Ann [inaudible] (one source mentions a "Gymnast" as a guest). Unknown content [but possibly a performance of What'd I Say, with band and Raelettes].
- 12 March 1974. Among the guests: Ray Charles. Unknown content.
- 19 November 1974. Guests: Ray Charles, Petula Clark, Madlyn Rhue, Orson Bean. Ray performed Louise* and Come Live With Me*.
- 25 March 1976. Guests: Ray Charles, Arthur Ashe, George Gobel, Orson Welles. Ray performed Then We'll Be Home (Sadies Tune).
- 16 February 1979. Guests: Ray Charles, Cheryl Hennington, Cindy Lynn Lawson, David Brenner, William Demarest. Ray performed Riding Thumb* and She Knows*.
- 1 February 1980. Guests: Ray Charles, Bob Hope, Teri Garr. Ray performed Some Enchanted Evening* and The Jealous Kind*.
- 2 February 1984. Guests: Ray Charles, George Jones, Charles Nelson Reilly, Holly Palance. Ray and George did duets on Friendship* and We Didn't See A Thing*.
- 18 March 1986. Guests: Ray Charles, Barbara Hershey. Ray performed Stranger In My Own Home Town* and Oh, What A Beautiful Morning*.
- 19 February 1987. Guests: Ray Charles, Lily Tomlin. Ray performed Mississippi Mud* and Come Live With Me*.
- 9 June 1987. Guests: Ray Charles, Madonna. Ray performed Chattanooga Choo Choo* and Yours*.
- 10 December 1987. Among the guests: Ray Charles, David Brenner. Ray performed Just For A Thrill*.
- 12 October 1988. Guests: Ray Charles, Cody Carr. Ray performed You Made Me Love You (I Didn't Want to Do It)* and There'll Be Some Changes Made*.
- 11 April 1990. Guests: Ray Charles, Richard Lewis. Ray performed I’ve Got News For You* and Oh, What A Beautiful Morning*, both with his own orchestra's rhythm section.
- 21 November 1990. Guests: Ray Charles, Father Guido Sarducci. Ray performed Elly, My Love* and Teardrops From My Eyes*.
- 16 April 1992. Guests: Ray Charles, John McEnroe, Tom Selleck. Ray performed The Brightest Smile In Town* and The Good Life*.
#18 (the appearance on April 16, 1992) was announced as Ray's "18th on the show, which was started in 1972". This suggests that the list is incomplete and that #1 doesn't belong here.
The complete history of all Tonight Show formats spans the period from 1962 to 1992. Before the Carson era Ray also appeared on one Tonight Show presented by Hal March (on 30 August 1960; see this).
For Ray Charles, late night talk shows have always been a great environment to plug new records (and an occasional book). In 1993 Ray was a one-time guest at Jay Leno's Tonight Show (see this). He also guested at several Late shows hosted by Ed Sullivan (see this and this), by Joan Rivers (see this), and by David Letterman (see this).
In most of shows in the list above Ray was interviewed by Carson. All or most of this footage has also survived.
The JohnnyCarson.com website licenses and showcases a number of the programs listed above (you can watch them in watermarked versions, but with good audio quality).
Elly, My Love and Teardrops From My Eyes (1990, November 21):