[Free88]

ChevyTech, today while crawling around under my truck to see where the noise was coming from I noticed that the sensor in the exhaust pipe had no wires coming from it. I checked all over for a while but could not find one. I looked in the manual and it showed a purple wire in the schematic number 412 going to connector D7 on the ecm. I can not locate this wire and was wondering if you had any idea as to where this may be located. It looks like a two wire connector on the O2 sensor but only shows one wire in the schematic. Thanks