can some one help me

i just got a remote start and i cant find my tach input wire on my 97 tahoe does any one know were it is?the installation manual say this input provides the remote start with information about the engines revolutions per minute (rpm).it can be connected to the negative side of the coil in the vehicle with conventional coils.to test for a tachometer wire,a multi-meter capable of testing ac voltage must be.thetach wire will show between 1v and 6v ac at idle and will increase as the engine rpm increase.in multi-coil ignition systems,the control module can learn individual coil wire.so now you know what the installation say's were can i look for this wire at and if some one might know the color of it LOL :) IF YOU  CAN HELP ME PLEASE I WOULD BE VERY HAPPY THANKS!!!!