GM Genuine Parts A/C Drive Belt Idler Pulleys are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These A/C drive belt idler pulleys are the components that route the drive belt to accommodate other engine compartment components. The A/C drive belt idler pulley is used for applications where the A/C compressor is driven by a separate belt. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some GM Genuine Parts may have formerly appeared as ACDelco GM Original Equipment (OE).