please tell me where the knock sensor is located on my blazer

Get urself a Haynes repair manual. It'll pay for itself over and over.

http://www.2carpros.com/questions/chevrolet-blazer-2000-chevy-blazer-knock-sensor-location Copy and paste the link above: Please note: this is a very reliable part that 'RARELY' fails so do some testing before replacing!!.. Don't ever replace a sensor just because it has a fault code for that segment.. There's more possibilities!