"Melody's Malady" may be as bright and colorful as a holiday ornament, but it is probably also as hollow. The half-hour fantasy was produced by the good-deeds detail at WJLA-TV and airs tonight at 7:30 on Channel 7.

The story, by producer Mark Young, does a slight and unimpressive variation on a Lorne Michaels skit for an old Lily Tomlin special; Lily played a clown, replete with round red nose, born to an unsuspecting "normal" couple. "Melody" is about a little girl who never smiles until a clown in a derby shows her the secretsof clownsmanship. She joins the happy band and smiles her little socks off from then on.

You can get away with almost anything in the name of wholesome whimsy at this time of year, and "Malady" may please easily pleased young viewers in the audiences. It does represent a lot of work by a lot of people, including 12-year-old Heather Schulz of Springfield, Va., the amateur chosen to play Melody, and likable David Wisniewski of Bowie, Md., as the clown.

The program was taped outdoors in Rock Creek Park and at the National Zoo, but director Kim Thomas had some tape editing problems, and the rhythms are uncertain. Worse, thought, is the general dearth of originality. Midway in the showwe are treated to a lip-synch version of the late Irene Ryan's recording of "No Time at All" from the Broadway hit "Pippin."

If they were going to have songs, they should have written new ones, as was so imaginatively done for two classic local children's specials, "You, Me and Them, Too" and "Imagine and Make It Real," produced in 1975 and '76 by Nancy Croce for WRC-TV.

Local statiions expect gushes of grateful congratulation when they rev up their resources (and their promotional machinery) for this kind of effort. We can be grateful that "The $100,000 Nane That Tune" is preempted, it is ture, and that many local performers were given a monent of access to the air. But "Melody's Malady" suffers from malaise that makes it a questionable bequest.