John Ray took his campaign for the D.C. Democratic mayoral nomination yesterday to one of his weakest areas of support, while rivals Charlene Drew Jarvis stumped for votes at a giant senior citizen complex and Sharon Pratt Dixon taped a commercial she hopes to air before Tuesday's primary election.

As some of the candidates and their aides showed signs of strain in the grueling race for the Democratic nomination, Ray won the endorsement of the Washington Afro-American newspaper and a group of 45 business owners in Ward 5, a section of Northeast Washington where he said his support needs strengthening.

Meanwhile, Walter E. Fauntroy maintained a relatively light schedule, campaigning at nursing homes in Northeast and Northwest, and David A. Clarke scheduled a two-hour rest to be fresh for a television interview and debate later in the evening.

Clarke is not the only person feeling the wear and tear of the primary campaign as it draws to a close. When Ray stopped in the Brookland neighborhood for the business group's endorsement, his aide Norm Neverson kept shouting "John Ray!" even though his voice was cracking.

Ray, who has been criticized by Fauntroy and Jarvis for accepting large developer contributions, was endorsed by the Ward 5 Business Organization, a group whose leaders said was formed in part to monitor the encroachment of commercial developers.

Carl Fairbanks, a commercial printer who has maintained a shop in Brookland for two years, said he was supporting Ray because "he makes a forceful appearance."

Ed Friedson, the owner of Capitol Nissan Inc. on Rhode Island Avenue NE, said he had a hard time deciding among the five Democrats, but settled on Ray because "he's the kind of person we need to come out of the mess we're in. He's honest and he'll work not just with business people -- we're citizens too."

In an interview, Ray expressed some concern about the high percentage of undecided voters in recent polls, adding that a poll conducted last week for his campaign showed 36 percent of those in Ward 5 still had not made up their minds about the election.

Ray, an at-large D.C. Council member who lives in Ward 5, said many of the ward residents who are "still on the fence" included hundreds of D.C. government workers and public housing residents who have been longtime supporters of Mayor Marion Barry.

Noting that Dixon has run largely as an outsider to the District's elected political establishment, Ray said, "The only thing that worries me is if a lot of people say, 'Give this person {Dixon} a chance -- throw 'em all out.' "

Ray added that his own polling showed no such mass movement of voters toward Dixon, although he did say she was "in second place now" and "running a smart campaign."

David E. Byrd, Dixon's campaign manager, said she taped a 30-second commercial yesterday that stresses what has become the central theme of her first bid for elective office: "It's time to clean house."

Byrd said the campaign had $24,000 to spend to air the spot on commercial television, most of it on Monday, election eve. Most of the time available for political commercials this weekend has already been purchased -- much of it by Ray.

The endorsement of Ray by the Afro-American drew a complaint from Clarke, the only white mayoral candidate, who said he was not afforded the same front-page profile that most of his opponents had been accorded in the earlier stages of the campaign. Clarke, who was interviewed for such a piece last month, said he believed the resignation yesterday of the newspaper's city editor, Robyn-Denise Yourse, was prompted in part by the way the publication had treated his candidacy.

Yourse could not be reached for comment.

"I don't think the Afro was fair in publishing profiles on all candidates but one," said Clarke, the D.C. Council chairman. " . . . I call upon all media to be fair and balanced in their presentations."

Afro-American Publisher Frances L. Murphy II said Yourse resigned because she was "very disgruntled," but not by the Ray endorsement. Murphy also said there were "too many" profiles to publish to make room for Clarke.

Jarvis, campaigning with Effi Barry, invoked the mayor in remarks yesterday at a luncheon with residents of the Capitol View Senior Center in Southeast Washington.

"As mayor, I will continue to work to meet your needs and I will continue to come to you for your advice and help," Jarvis said.