Dig even deeper. While the Americans bombed the German owned truck factories, they avoided bombing the Ford plant in Cologne. It continued to churn out trucks for the German armed forces (at a slowing rate due to supply chain issues) until it was overrun by American troops.
The plant did suffer some minor bomb damage from planes that missed their targets. It resumed production of trucks in May, 1945. The British didn't allow automobile production until 1948.
Ford Motor Company Sued the US Government for Bombing Its Factories in Nazi Germany
It was British Major Ivan Hirst who got the Volkswagen factory in Wolfsburg back up and running as a car factory. It had been used as an armament factory by the Germans, and had been mostly destroyed.