The lights were low in Blues Alley last night and the ambiance was mellow, veeerry mellow, and as in shadowy, smoke-filled clubs so many years ago, a movement was about to be born. A full house of jazz devotees gathered to hear Nancy Wilson sing, to hear Rep. John Conyers (D-Mich.) speak, albeit briefly, and to witness the first official function of the Parker-Coltrane Political Action Committee.

Formed last spring to recruit and financially support black and liberal candidates for public office, particularly in the South, PAC bears the names of the late jazz musicians Charlie Parker and John Coltrane because, as Conyers put it, "it speaks to black Americans' cultural heritage. It has a revolutionary tone muscially that we'd like to translate into the political arena.

"We're also trying to involve more people than orthodox political channels do," Conyers continued. "People are attracted by entertainers -- like Stevie Wonder, Nancy Wilson, Joe Williams -- rather than stuffy pols."

Wilson, who brought the Alley to a slow burn in her white jump suit last night, was entertainment enough to get 160 politically sympathetic people to pay $100 per ticket. "I'm just trying to do my part because I've been there for a long time," said Wilson, who helped raise money for Conyers' initial election to Congress in 1964 and for about 20 years has performed at benefits on behalf of what she calls "decent officials."

This PAC was in the works for a long time, Conyers said, but "we perhaps have Sen. Jesse Helms [R-N.C.] to thank for the final push. If he can put $4 million into moving this country in the wrong political direction, then we need to respond." Conyers also said efforts are being concentrated in the South because "there's a multitude of black voters without representation."

Among the guests last night were prominent black business people, including developers Pris- cilla and James Adkins; Dr. Edward C. Mazique; City Councilwoman Hilda Mason; Vice Chairman for the U.S. Commission on Civil Rights Mary Berry; and attorney Joseph Rauh.

Rauh, who is a fixture in such organizations as the American Civil Liberties Union, the NAACP and Americans for Democratic Action, said, "A lot of my friends have made more money than me, but civil rights is much more fun."

"I don't know how to explain to my children what is happening in the world," Wilson told her audience between numbers. "My son is fighting my battles with me and he shouldn't have to. He should fight his own."

Vocalist Nancy Wilson presented a program to benefit the Parker-Coltrane Political Action Committee last night at Blues Alley, and from the instant she stepped on the bandstand, it was clear she was in her element. Her strengths lie primarily in her ability to maintain a sense of one-to-one communication. To experience her adequately one must study her subtle variations in facial expression, especially her eyes, for she is a consummate actress, even a comedian. Then again, one must be close to catch the nuances of her sometimes off-mike voice.

Wilson displayed her vast repertoire of vocal personas that range from cooing warbles to barge captain shouts, from elephantine roars to tiger cub growls. Her intonation is faultless, her pulse sure and her deft turning of a phrase emotionally convincing. Indeed, of cabaret singers, there are few to match her. Whether throwing herself body and soul into "The Masquerade Is Over" or declaiming the wry intro, over tinkling piano, to her early hit, "Guess Who I Saw Today," she was the complete entertainer.

Pianist Michael Wolff, her regular accompanist, Keter Betts on bass and drummer Harold Mann provided excellent support.