General Motors Co (GM.N) said a defective ignition switch linked to the recall of almost 3.4 million cars was made in China, where another car maker discovered a problem part earlier this year. The No. 1 U.S. automaker said in a filing on Tuesday with U.S. safety regulators that the switch used in the Chevrolet Impala and Monte Carlo, Buick LaCrosse and Lucerne, and Cadillac DeVille and DTS cars that were recalled on June 16 was made by China-based Dalian Alps Electronics Co Ltd.