S&C Electric Co., Chicago, withdrew its $4 million commitment to the Strong Opportunity fund and will move the money to the Vanguard Strategic Equity fund, said Mike Moses, financial services director. Trustees of the $55 million pension plan made the move because of the market-timing investigation into Strong Capital, Mr. Moses said. The Vanguard fund is also one of 10 investment options offered in the participant-directed $85 million 401(k) plan. No consultant was used. Drew Wineland, spokesman for Strong, could not be reached for comment by press time.