J.L. Hudson Co., largest department store in downtown Detroit, is closing its windows-despite entreaties from Henry Ford II and Mayor Coleman Young.

This symbolic shutting of an eye on the city comes at a time when the industralist and the politician are heading a campaign to get the world to take a look a Renaissance Center, a multi-million-dollar start at revitalizing the automobile capitals central business district that was dedicated last week.

"What we need is to get people to stay downtown to look at the shops after work," Ford said.

Young said he wants Hudson's to "show the same spirit the 51 partners have shown," a reference to the industrial and financial corporations that put up $337 million to build the "Rencen" a complex of four office buildings and a hotel with space for 100 shops. Backers of Detroit's newest landmark, which juts out of the skyline along the Detroit River, hope it will become the catalyst for development of the entire blighted central area.

Thus far, Hudson's has not succumbed to high-level preassure to reopen the closed half of its display windows, a move the company says resulted from manpower problems, not vandalism. Employees spent too much time decorating windows, time that could be used to spruce up the interior, the company maintains. Hudson officials claim that their suburban branches do very well without display windows.

While Ford and Young object to the 95-year-old emporium shutting its symbolic eyes, other Detroit residents are just thankful Hudson's isn't also closing its doors, for sales in the department stores have been declining steadily for two decades. For the three years prior to 1976, Hudson's flagship store on Woodward Avenue made a sight profit, but last year it went into the red. And President J.L. Hudson JR. repeatedly has warned there may come a time when a store may have to desert Detroit's main shopping district.

Detroit's dilemma-civic pride versus economic reality-recently was summed up by Detroit Free Press editor Joe H. Stroud.

"It seems to me that Detroit has long since lost the ability to dissuade a firm or an individual from making such a move by appels to civic obligation, or threats of boycott, or cries of shame," he said. "If this tide (of flight to the surburbs) is ever to be reversed, businesses must be given a business reason to stay, or to build, in the central city.A store is not a philanthropic or a civic institution."

Stroud suggested that the time is fast approaching when, as suburban growht slows down, business should look to the potential of the black population. "Altruism will never save the cities," he said. "Exploring underdeveloped market might."

Since construction began on Renaissance Center, 53 major new buildings or expansions have been completed or appoved in the central city. These projects total $207 million in private investments and $396 million in public funds. They include the $20 million Civic Center Plaza with its 120-foot-high fountain, located along the waterfront near the Rencen and another waterfront landmark, Cobo Hall Detroit's main convention center, garages, a courthouse annex, the renovated Stroh Brewery, and a pedestrian plaza, mall and canopy.

A $55 million, 2.5 monorail, federally funded, is planned to convey people around the central district. A sports arena is targeted for the warerfront, but construction is being fought by surburban interests who want it built nearer them.

Last week, Mayor Young announced he would try to move a planned new county jail from the center city where its construction would spoil Greek-town, a quaint old ethnic quarter whose restaurants and shops have become very popular with people working in the area. Wayne County Commission chairman John Barr protested, however.

"What do you mean, we'll be hurting Greektown?" he cried. "We'll be bringing more people into the area. There will be the added protection of more uniformed people."

While Detroit has taken on a tough reputation because of its high crime rate, a recent poll of taxi drivers indicated that nearly a third of them thought the center was the safest part of the city.

Robert E. McCabe, president of Detroit Renaissance, an organization of business leaders, commented that it was "highly doubtful" that new construction would have occured without RenCen. On the contrary, he maintained, further deterioration would have taken place.

As might be expected, RenCen has had some other effects not unanimously hailed. Some minority-group leaders are said to feel they have been excluded from plainning as well as benefits. Seventy per cent of the new towers' office tenants have been drawn from other downtown buildings; only 30 per cent have moved from ouiside the downtown. Land values along the waterfront have soared 500 per cent, according to Wayne S. Doran, president of the Ford Motor Co. subsidiary that developed RenCen.

Originally, Renaissance Center was planned as the first phase of a grandiose scheme that was to include riverfront luxury condominiums and other housing. The latter phases are now in abeyance, pending proof of RenCen's economic viability and its magnetism to draw more business industry and people into the core of the Motor City.

Industrilist max Fisher has announced plans for a $100 million, 2,500-unit high-rise development west of Cobe Hall, to be started this summer. However, latest reports are that he has not yet been able to secure sufficient private financing. In the new "uptown" business center, residential units have been or are being constructed on the Wayne State University campus and on the grounds of the cultural and medical centers.

Compared with industrial construction, there appears to be very little residential statistics for the first half of 1978 reveal that 2,339 permits were issued in Wayne County. Detroit, which is in that county, issued 433 permits, of which only 6 were for single-family homes.

Redevelopment of the eastern sector of the city appears to be ragged. Bordering on near-in Lafaysttee Park with its Mies van der Rode-designed town houses and high rises constructed in the 1960s is Elmwood Park, part of which contains low-and moderate-in-come housing. Another 185-acre tract, known familiarly as Black Bottom to its former residents-who include Mayor Young-has been vacant for several years except for rows of trees that were preserved. Elsewhere stand the dilapidated, boarded-up wooden shacks that once dominated the entire area. CAPTION: Picture 1, Rennissance Center, including the 73-story Detroit Plaza Hotel and four 39-story office towers, juts out of Detroits skyline. AP; Picture 2, Developers of the $337-million Renaissance Center hope it will spur revitalization of downtown Detroit. Other construction is under way. Renaissance center Photo