For 13 years, Major M. Johnson has maintained he never deserved his nickname of Northern Virginia's "red light rapist" or the two life sentences he is serving for abduction and rape.

Now a federal judge in Alexandria has set aside his 1973 convictions and ordered the State of Virginia to give Johnson, who will become eligible for parole in a year, a new trial or release him within 90 days.

U.S. District Judge Albert V. Bryan Jr. ruled last week that Johnson's jury was given instructions that improperly shifted the burden of proof from the prosecutor to the defendant.

"I never got a fair chance in the first place," Johnson said yesterday from the Buckingham Correctional Center in southern Virginia, where he is serving his sentence. "I am innocent and I am going to prove it. This time I'm counting on justice."

Johnson, 54, was convicted in September 1973 in Fairfax County Circuit Court of an attack on one woman. There had been as many as seven similar crimes in Fairfax County in which women motorists were attacked after being stopped by an unmarked car equipped with a flashing red police light.

The crimes received wide publicity and police advised women traveling alone to stop only for cars with sirens as well as flashing lights. Johnson turned himself in to the FBI after he was told there was a warrant for his arrest.

A 26-year-old woman testified at his trial that after she stopped her vehicle in response to the flashing red light on a car behind her, she was dragged from her car and driven to a secluded place where she was raped.

She told police that she had torn several blond hairs from her head and left them on the rear seat of the rapist's car in an attempt to help identify him.

Although a police search found blond hair in Johnson's car, FBI lab tests were not able to positively identify them as the woman's.

Two defense witnesses testified that Johnson had been with them when the rape took place.

Johnson has always maintained his innocence, saying that the woman mistook him for another man. He said he has spent years studying cases similar to his, and did the research for almost all of the many petitions he has filed to gain a new trial.

"The night they picked me up, the woman said I was not the man who raped her," he said yesterday. "Then she changed her mind. This is with me every day of my life. I will fight until it is done. Even if I get parole first, I will still fight for my name."

Robert F. Horan Jr., Fairfax County commonwealth's attorney, could not be reached yesterday to comment on whether the county will try Johnson again. Assistant Virginia Attorney General Frank S. Ferguson said the state may appeal Bryan's decision.

"I have no doubt that the evidence was properly before the jury," Ferguson said. "It was up to them to make the decision and they made one."

Judge Bryan ruled that the instructions given by the judge, James C. Cacheris, who, like Bryan, is now a federal judge in Alexandria, contained a paragraph that "violated the 14th Amendment's due process requirement that the prosecution must prove every element of a crime beyond a reasonable doubt."

Johnson said all he wanted to do was go back to work at the gas station in the District that employed him when he was arrested.

The station has since been closed.