Heres the story. 86 Jimmy, 89 drivetrain( 350, 700r4, 241) including the computer and harness. My convertor is not locking up... ever. The Haynes manual is no help whats so ever. From what I've read, the converter is supposed to lock up at speeds of 25MPH+ and in third and fourth gear. What are the other things that must happen for it to lock up? Are there any? I personally though it was controlled by the computer( ie no vacuum switch) but maybe I'm wrong. Anyways, there are 3 wires in the 4 pin connection to the tranny. Does anybody know what each one is for? I believe mine are pink, blue and green. I would assume that pink is power to the switch and the others are the ground wire( probably green) and the signal wire. am I right? Once I figure this out I'll hook a multimeter up to the hookup to see if everything is right, then take it for a drive to see if the lockup signal is there. If the signal is there what else is wrong? TIA for all the help guys.