NEW YORK — Jerry Van Dyke, the younger brother of Dick Van Dyke who struggled for decades to achieve his own stardom before clicking as the dim-witted sidekick in television’s “Coach,” died Friday in Arkansas, according to his manager. He was 86.John Castonia said Van Dyke died at his ranch in Hot Spring County. His wife, Shirley Ann Jones, was by his side. No cause was immediately known.Van Dyke had an affable, goofy appeal, but he spent much of his career toiling in failed sitcoms and in the shadow of his older brother, even playing the star’s brother in “The Dick Van Dyke Show.”Until “Coach” came along in 1989, Van Dyke was best known to critics as the guy who had starred in one of television’s more improbable sitcoms, 1965’s “My Mother the Car.” Its premise: A small-town lawyer talks to his deceased mother (voiced by actress Ann Sothern), who speaks from the radio of an antique automobile.Other bombs included 1967’s “Accidental Family,” in which he was a nightclub comedian, 1970’s “The Headmaster,” in which he was a gym teacher and 1963’s “Picture This,” a game show that lasted only three months. He also joined “The Judy Garland Show” in 1963, to provide comic relief, but was fired at the end of the season.