INTIMATE PORTRAIT: LINDSAY WAGNER N.F. Mendoza Apr 23, 1999 10 p.m. Sunday Before anyone questions the viability of an hourlong portrait of an actress best known for 1970s pop-culture hit "The Bionic Woman" or her longtime high-profile job hawking cars in TV commercials, let it be said that it would be difficult after watching this docu to not like Lindsay Wagner. She comes across as warm and sincere. Wagner began her career as a child actress, became a successful model and TV actress and finally focused her career in "message telefilms." She candidly discusses her troubled childhood, the stress and responsibility of "Bionic Woman," her four failed marriages and her devotion to her two sons. As is the case in other "Intimate Portraits" there's unnecessarily maudlin music and repetitive interviews. How many people need to remind the audience that Wagner "works from her heart"? Certainly more clips from her many projects could demonstrate that, as would a comprehensive look at her films. Wagner's aunt, Linda Grey of "Dallas," offers familial insight, as does Wagner's boyfriend. The new trend in "Intimate Portraits" is for the show to be narrated by former co-stars (in this case Robert Urich), which seems self-indulgent. Commentaries by the narrator about their experiences with the subject are a little irritating. Still, this documentary, written and produced sensitively by Ruth Rivin, is an entertainingly revealing look.