TV REVIEW; 2 SITCOMS, 'MR. SUNSHINE' AND 'JOE BASH,' ON ABC

OFFICIAL ''seasons'' being things of the past, the networks now tinker with their schedules all year round. Among the new series introduced over the past several weeks, for instance, are ''Mr. Sunshine'' and ''Joe Bash,'' both on ABC. Neither has been especially promising as far as ratings are concerned, but both certainly try to be different.

The hero of ''Mr. Sunshine,'' a situation comedy that can be seen on Fridays at 9 P.M., is blind. This is not a first for sitcoms. Several years ago, there was a rather unfortunate pilot featuring a blind college student. In this instance, the central character is a college professor and, bucking the odds, he can be genuinely funny. Portrayed wonderfully well by Jeffrey Tambor, Paul Stark is a demanding, acerbic and unquestionably bright fellow who lost his sight, and subsequently his fretful wife, as a result of an auto accident several years ago. The ''Mr. Sunshine'' label is ironic. Paul's wit tends to be caustic. As Grace (Nan Martin), his personal secretary, warns him: ''You can't afford to be bitter; you're not that pleasant to begin with.''

In addition to sarcastic Grace, Paul's sitcom mix includes his dizzy landlady (Barbara Babcock), a no-nonsense female friend (Cecilia Hart) and a haughty but bumbling teacher colleague (Leonard Frey). Adroitly, the series makes clear that it is not about being blind. ''Mr. Sunshine'' is about an interesting, intelligent man who happens to be blind. When asked if he is really blind, Paul assures the doubter that ''bats use me as a role model.'' It is, undeniably, a tricky situation for standard television comedy, but the people in charge, clearly sensitive to the pitfalls, have good track records. John Rich, veteran director for Norman Lear and MTM Enterprises, and Henry Winkler, once of ''Happy Days,'' are the executive producers. Gene Reynolds, instrumental in the success of TV's ''M*A*S*H,'' also had a hand in developing ''Mr. Sunshine.'' Add Mr. Tambor's thoroughly disarming performance, and there is good reason for Paul Stark to be one of the brightest presences on the new-series landscape.

''Joe Bash,'' on the other hand, is something else, something so unusual for a half-hour format in prime time that it could be either dismissed as a disaster or hailed as a breakthrough. After watching its first three episodes on Fridays at 9:30 P.M., I found myself getting used to its offbeat ways and actually beginning to like its oddball characters. ''Joe Bash,'' created by Danny Arnold, who is best known for the ''Barney Miller'' series, revolves around life as a policeman in a New York precinct in lower Manhattan. Joe Bash is nearing retirement and just wants to get through the rest of his tour with as little effort as possible. His new partner, Willie Smith, is young and still eager to help humanity. The two patrol their beat on streets that are clearly part of a studio set. There is no laugh track to signal the viewer as to whether Joe's misanthropy is really supposed to be funny. ''Joe Bash'' moves to its own special beat, apparently bent on demolishing every well-established cliche in sitcom territory.