A Virginia House committee, given graphic details of automobile deaths and injuries, approved a bill today that would make seat-belt use mandatory, after turning aside a strong move to cripple it by Del. Robert E. Harris (R-Fairfax).

On a 9-to-7 vote, Harris lost his bid to eliminate a $25 fine for noncompliance, a change that would have left the bill with little enforcement power, officials said.

Harris said later he doesn't wear seat belts "because they constrain me and I feel I can operate my vehicle better without them ." He said he believes "75 percent of the people in my district" oppose such a law because it would "infringe on individual rights."

The bill, approved 11 to 6 by the House Roads Committee, would require drivers and any other riders in the front seat of a vehicle to wear seat belts. The bill would make it the responsibility of the driver to ensure that any front-seat passengers from 4 to 16 years old are restrained. The bill's chances in the legislature are considered uncertain.

Virginia law already requires that children under 4 years old be placed in safety seats in either the front or back seats. Harris, one of the most outspoken opponents of the new bill today, said he had voted for the child safety seat law only "after we watered it down."

Today's bill would exempt rural mail carriers, adults who obtained a written medical excuse and law enforcement officers under limited conditions. The bill would not apply to passengers in public carriers such as buses.

Some legislators indicated they opposed the bill because of the perception that they were being coerced by the federal government. The U.S. Department of Transportation has said it will require auto makers to install airbags -- bitterly opposed by the auto companies -- if states representing two-thirds of the population have not passed mandatory seat belt laws by 1990.

If the General Assembly approves the bill, Virginia will become the fourth state to approve such a law, officials said. New York, New Jersey and Illinois already have mandatory seat-belt laws.

It is the second bill this session to be criticized because of federal policy decisions that some see as intervention. Some legislators also have attempted to put off votes on a measure to raise the drinking age for beer to 21, in part because the DOT has said it would cut off federal highway funds to those states that don't.

"A death or an injury is a cost to us all," argued Del. J. Samuel Glasscock (D-Suffolk), sponsor of the seat-belt measure. Glasscock told reporters later that he regretted the appearance of federal coercion but said, "If the idea's right, you should do it."

Glasscock led a procession of witnesses who jammed the committee room in support of the bill, including physicians and rescue associations, Department of Motor Vehicles employes and insurance and manufacturers' representatives.

Glasscock released figures showing that of 1,352 traffic deaths during 1982 and 1983, only 35 of the victims -- or less than 2 percent -- were wearing seat belts.

Only one witness, a resident of suburban Richmond who said he had been driving for 20 years, spoke against the measure, saying a seat belt "handicaps me in making some maneuvers."

J. Ronald Nowland, executive director of the Virginia Automobile Dealers Association, was among those supporting the bill.

Nowland said the dealers support the law partly to avoid switching to airbags, which he said could add about $800 to the price tag of a car compared to about $200 to $300 for an improved automated seat-belt system also being considered.

Both Glasscock and Del. William P. Robinson Jr. (D-Norfolk) later said they had survived automobile accidents by wearing seat belts.

Robinson, whose sports car was struck by a much larger car in 1971, said in an interview, "But for a seat belt, I wouldn't be here."