FORD Motor Company Chairman Alex Trotman praises the US-Japan auto trade pact signed Aug. 15, but he says another player poses a bigger threat to the world auto market in the next five years - South Korea. Currently, South Korea has a domestic car market that can sustain 2 million vehicles, says Mr. Trotman, in an interview here this week. But by 1998, the country plans to increase production to 5 million units - about 3 million more units than the Korean market could absorb. Trotman says he sees South Korea following the same aggressive plan as the Japanese in gaining market share. ''They attack very effectively new markets that open,'' he says, citing Australia and New Zealand as examples. Ford itself is building a right-hand model of its all-new 1996 Taurus for launch in these two markets. Ford does business in about 200 countries and has manufacturing facilities in about 30. The automaker is honing in on Asia, Trotman says, and is currently pursuing deals with manufacturers in Thailand, China, Indonesia, Vietnam, and India. The Ford chairman was at American Engineered Components Inc., in Cambridge, Mass., this week to promote the 1996 Taurus and Mercury Sable. The 175-employee company, which makes parts for the new cars, was the last stop on a 65-city tour to some of the automaker's 235 suppliers that helped build the new models. New look for Taurus The 1996 Taurus is the first major overhaul since the Taurus's launch a decade ago. Ford plans to roll out about 500,000 Tauruses and Sables a year, Trotman says. They will hit showrooms Sept. 28. ''This is a totally different automobile,'' he says. ''I personally foresee that this will be a landmark vehicle that will have other people chasing us.'' Trotman contends that these are important car models both for Ford and in terms of employment in the United States. Of any car built here, he says, the Taurus is the No. 1 provider of jobs. Trotman says he expects reasonable car sales to continue and anticipates a stronger '96. He estimates that 15.4 million new cars and trucks will be sold in 1995, compared with 15.1 million last year. Car prices below inflation The price of US automobiles has risen at about 2.4 percent a year, he says, below the 3.5 percent rate of inflation as well as the rate of increase of import prices. Regarding electric cars, Trotman says he is urging states to delay a requirement that Ford and other carmakers start selling electric vehicles in 1998. ''We're simply not ready to meet a mandate,'' Trotman says. To meet the mandate means selling a small electric truck that has a 30-mile range and will cost more than $30,000, he explains. ''I don't think many people will buy it.'' Trotman says he can't say specifically when Ford will be ready to put a car on the market. But he says the goal is to build a vehicle with a driving range of 200 to 225 miles before the batteries need recharging. ''There is this growing view that if you keep auto manufacturers feet to the fire and give them a deadline, they can invent anything,'' he says. ''Well, that's not going to happen.''