Franco Harris' playing time for the Seattle Seahawks was brief, but its effect long-lasting as he helped his new teammates rally to a 31-17 victory over the San Diego Chargers today.

Harris, the former Pittsburgh Steelers running back signed as a free agent last week by the Seahawks, rushed 14 times for 46 yards as a backup to starter Eric Lane. The yardage left Harris 317 yards short of Jim Brown's all-time pro football rushing record.

Harris didn't enter the game until late in the first quarter, when the Chargers had built a 10-0 lead. His first three carries covered 13 yards, including a key four-yard gain for a first down that started Seattle's first touchdown drive.

His presence lifted the Kingdome crowd of 64,314 and then the Seahawks' offense. Seattle went on to score 31 straight points.

"His presence helps," said Seattle Coach Chuck Knox, whose No. 1 runner, 1983 AFC rushing leader Curt Warner, was sidelined last week with a season-ending knee injury. "Franco was very limited in what he could do because he had only two days of practice with us.

"He moved the ball forward all the time . . . four, five yards every time he had it. He's still not familiar with the offense, but he's going to help in the weeks to come."

Harris agreed.

"My biggest worry was not to fumble," he said. "This is the first time I've worn pads since last year and I had to go back to the basics. I wasn't sure just how I could help the team today, but I didn't want to hurt them. Now I'll have a full week of practice and a lot of the uncertainties will be out of the way."

Harris started Seattle's first scoring drive and quarterback David Krieg finished it.

Krieg, who struggled with one-of-eight passing accuracy to start the game, finished 18 of 38 for 263 yards, ran for two touchdowns and passed for one.

San Diego quarterback Dan Fouts, meanwhile, struggled through a 23-of-40 performance with four interceptions. In addition, San Diego lost four fumbles after driving to a 10-point lead on Rolf Benirschke's 43-yard field goal and Fouts' 61-yard touchdown pass to Bobby Duckworth.

On Seattle's first touchdown drive, the Seahawks went 63 yards in 15 plays -- Krieg completing passes of 17 yards to Steve Largent and 11 yards to Paul Johns -- before Lane ran a yard for the touchdown with 11:34 left in the half.

The Seahawks tied the score, 10-10, with one second left in the half when Norm Johnson kicked a 41-yard field goal. The score was set up by a 51-yard pass from Krieg to rookie wide receiver Daryl Turner.

Krieg made it 17-10 midway through the third period on a 37-yard touchdown scramble. He fled the pocket, slipped away from Bob Gregor and ran down the sideline into the right corner of the end zone.

"It was a scramble," said Krieg. "Once I got past the line of scrimmage, I knew I had the first down, so I just kept running to get all the yardage I could. I was surprised."

Krieg's second touchdown run was no surprise. He rolled to his right on a three-yard keeper, diving into the end zone to give Seattle a 24-10 lead with 14:10 left in the fourth quarter.

The touchdown ended a nine-play, 71-yard drive in which Krieg completed three straight passes totaling 49 yards. A 25-yarder to tight end Mike Tice between defenders Miles McPherson and Andre Young gave Seattle a first down at the five-yard line. Krieg scored two plays later.

A fumbled punt return by San Diego's Lionel James set up Seattle's final scoring drive at the Chargers' 22.

Three plays later, Krieg found Turner crossing over the middle and hit him in stride for a 22-yard touchdown and a 31-10 lead.

The Chargers scored late when Fouts passed four yards to Eric Sievers with 30 seconds remanining.

Fouts' first-quarter touchdown pass to Duckworth deflected off defender Kenny Easley's foot as Easley and teammate Dave Brown tried for an interception on the overthrown ball. San Diego played without two of its star players, tight end Kellen Winslow and running back Chuck Muncie. Muncie missed the team plane, saying his automobile was vandalized, and flew to Seattle on a later flight. Coach Don Coryell, however, refused to allow Muncie to join the team and sent him back home.

Winslow decided late last week to return to the team after saying he was retiring. However, the Chargers were unable to activate him for the game.

Asked about their absence, Chargers Coach Don Coryell said, "I certainly don't think that had a bearing on the ball game."