mwaters

My 97 ES 300 is throwing knock sensor codes 0325 and 0330 with CEL. From the posts I've read on CL, this may be caused by faulty wiring harness exposed to heat over time. So rather than tackle a big job to replace sensors, or paying big bucks to dealer, I figured I'd try to replace the harness ($27 from Lexus dealer). So, I bought part # 82219-07010 but can't seem to figure out where it goes. Lexus gave me a diagram but I can't find corresponding wire. What am I missing? Do I have to take off the manifold to get to it? (ugh!) Thanks for any help!