The Virginia highway commission, one member short because of the forced resignation of Northern Virginia Commissioner William B. Wrench last week, reaffirmed today its support for a Springfield Bypass route that would benefit Wrench's property.

The eight commissioners present first reluctantly rescinded their August vote on the advice of state Attorney General J. Marshall Coleman who said Wrench had violated the spirit of the state's conflict-of-interest law by voting on the route of the $200 million Fairfax County highway. Less than an hour later, the commissioners voted 8 to 0 to keep the road where Wrench had recommended.

"We relied upon our commissioner in that district as we always do," said commissioner Richard G. Brydges of Virginia Beach, as his colleagues chorused their agreement. He said he saw no reason to change the route.

Supporters of Coleman's Republican race for governor hoped the reconsideration would end once and for all the political fallout over Wrench, a member of Coleman's finance committee. Reaction from Democratic candidate Charles S. Robb and from Northern Virginia officials indicated the repercussions would continue.

"The appearance of impropriety is still hanging over it," Robb said after a Northern Virginia Press Club lunch in Springfield.

Fairfax County supervisors, who unanimously had supported a different route, reacted with dismay to the commission vote and threatened legal action. Seven supervisors -- along with the county executive, transportation director, assistant transportation director, information director and a supervisor's aide -- had traveled here this morning to plead their case.

"I thought they would at least give the board of supervisors a chance to give some input," said Supervisor Sandra L. Duckworth. "They just wanted to justify their decision," said Supervisor Martha V. Pennino.

"They don't even want to talk about sitting down and talking about it," said Supervisor Thomas M. Davis III, a Republican who said the absence of a Northern Virginia representative on the 10-member board made matters worse. "It gives it the flavor of Richmond and the other areas imposing on us."

The state-approved alignment, which Wrench recommended and voted for last month, brought the 35-mile road close to three of his business parcels and put half an interstate cloverleaf on a 387-acre tract owned by his lawyer, who owns hundreds of acres along both routes.

Disclosure of Wrench's holdings by The Washington Post put Coleman in the embarrassing position of investigating his own supporters. Wrench, his lawyer John T. (Til) Hazel Jr., and Hazel's land-owning partner Milton V. Peterson all serve on Coleman's campaign finance committee.

Coleman returned Wrench's $1,100 campaign contribution and caucused with Republican Gov. John N. Dalton before Dalton asked Wrench to resign. Democrats have charged the case underlined the need for Coleman to quit his attorney general post while he is campaigning for governor.

Robb called on the commission to reconsider its action. "They clearly owe it to the people of Northern Virginia," he said. "At the very least, it's gross insensitivity."

Several highway commissioners said their route simply serves traffic better. A state planner testified today that the county alignment would put new interstate interchanges too close to existing ones on both I-66 and I-95.

"I'm sure there are a number of property owners through there," said commissioner T. Ray Hassell III of Chesapeake. "We're not privileged to know who they are and we're not interested in who they are."

The commissioners listened politely for l0 minutes to Fairfax Board Chairman John F. Herrity's plea for more negotiations, but they had little sympathy for the county's position.

"The concern for the motoring public has got to transcend the interests of local government," said William T. Robinson, a commissioner from West Point.

Several Fairfax supervisors said they now will vote to hold public hearings to change the county and regional master plans to accommodate their favored alignment. Once that is done, they said, the state could not receive federal funds for its own route.

Davis said that course could kill the Springfield Bypass, which county leaders unaminously support, but which faces uncertain funding.

"It puts the project in jeopardy," Davis said. "I would be reluctant to stop the whole project for that . . . The road is extremely important."