LIKE THE LEGENDARY thin man trapped in a fat body, there is in this recent novel of John Weitz a potentially good book trying to emerge. Friends in High Places is an ambitious attempt to describe the life of a German not particularly interested in politics, before the Second World War, during the war and after it, when he attempts to become a U.S. citizen.

Karl Dorn, or Charly to his American friends, is the average man who likes his work, doesn't think much about politics, and has decent instincts which lead him ultimately, if not to heroic action, at least to actions courageous enough to earn respect. As salesman in Berlin for a prestigious German firm which manufactures cars he has to meet with the S.S., and is indeed photographed with Hitler. He is taken prisoner in North Africa and brought to the United States. His wife, Hilde, passionately anti-Nazi and a member of an underground, dies while saving Jewish children in Berlin. At the end of the war Karl rejoins his old firm and comes to this country to sell its cars. An application for naturalization reveals his Nazi association, and the retelling of his past is used to vindicate and explain him.

Weitz -- the fashion designer -- has written of prewar and wartime Germany with insight and a commendable sense of place. His Berliners are distinctive people with their own characteristic patois. The idea of examining how decent men and women react to totalitarian regimes is always important, and Weitz does illustrate the difficulty of categorical absolutes. But Karl Dorn, as a man and not as an illustration of a dilemma, is a failure. He is like the cars he sells: high gloss but little else.