The D.C. City Council gave preliminary approval yesterday to a bill that would make the wearing of seat belts mandatory for anyone riding in the front seat of a motor vehicle driven in the District of Columbia.

Under the measure, which is expected to receive final council approval in two weeks, a driver or front seat passenger not wearing seat belts could each receive a $15 ticket. Police officers, however, would be able to issue such tickets only after they have stopped drivers for some other offense.

The issue sparked a long debate, with some council members arguing that although seat belts may save lives it is not the city's responsibility to force people to protect themselves.

In other action, the council gave final approval to a measure that substantially amends the city's cable television franchise agreement and transfers the cable franchise to a limited partnership formed by Tele-Communications Inc., a Denver-based firm, and District Cablevision Inc., the Washington contractor origninally awarded the city's 15-year cable franchise.

Two council members, Carol Schwartz (R-At Large) and John Wilson (D-Ward 2) voted against the measure. The franchise changes must now be approved by the mayor and undergo a congressional review period.

"I'm really glad it's over," said District Cablevision President Robert L. Johnson.

Johnson said his company will begin construction of the 54-channel residential cable television network next year and plans to have some District homes wired for cable by next summer. The firm's construction schedule calls for the entire system to be completed by 1990.

District Cablevision had requested the franchise modifications after failing to raise enough money to construct the cable system. Yesterday, District Cablevision presented the council with a signed limited partnership agreement under which TCI of D.C. Inc., a subsidiary of TCI, would provide a total of $45 million in cash and loans to construct the cable system.

While the cable modifications had been the source of intense negotiations and heated debates in recent months, the mandatory seat belt bill dominated the council's attention yesterday.

City Council member H.R. Crawford (D-Ward 7), tried unsuccessfully to amend the bill to require only persons under 16 and District government employes on duty to wear seat belts.

"I don't believe that the government should be intruding into the personal decisions of our citizens where it has no compelling state interest and where only the citizens may endanger themselves," Crawford said.

City Council Chairman David A. Clarke and Schwartz agreed with Crawford but a majority of the members argued that Crawford's amendment would gut the bill.

City Council member Hilda Mason (Statehood-At Large) said that one of her grandson's 17-year-old friends, who was not wearing a seat belt, recently died after the car in which she was riding hit a tree. "The most important thing is we're trying to save lives," Mason said.

Initially the seat belt bill had exempted taxicabs, ambulances and vehicles used for sightseeing, funerals and farm purposes. The council amended the legislation so that only farm vehicles would be exempt.

At least 12 states have passed mandatory seat belt laws. Maryland and Virginia legislators rejected such bills earlier this year.

The council added a provision requested by council member Betty Ann Kane (D-At Large) that says the District's seat belt measure would expire if the U.S. Department of Transportation tried to use it to void a federal requirement that automatic crash protection devices must be available in all cars sold in the United States beginning Sept. 1, 1989.

The California legislature has adopted a similar provision in response to the automobile industry's lobbying in favor of an escape clause in the federal legislation. That clause says the automatic crash protection rule would be rescinded if states with two-thirds of the nation's population adopt mandatory seat belt laws by April 1, 1989.