how are you suposed to tell the diffrence between the knock sensor wire and the fan switch wire, they both have the same connector?

 

Color is your best bet. Either check a helms manual (which is a must have) or go to the spark control module which should be located next to the brake booster on a bracket on the firewall. find the wire color that matches the one on the knock sensor connetctor. In my 85 it was blue. I don't know if it's the same in 87.

 

the ESC has a black and a white wire coming out of it and the knock and fan wire is black and the other is white so that doesnt help and its not in the manual what color it is

 

With key on, and a/c off, ground the wires one at a time - the one for the fan should make the fan come on when grounded, if I remember correctly.