78 Chevy wiring question-Truck won't shut off at the key
 

Little back story, i had to replace the wiring harness as the prior owners fried the original, i was able to find a clean 78 unmolested harness, everything has been plug and play. My one issue is when i go to shut off the truck at the key it's not killing it. So to killing the truck i have to unplug the lead that is coming off the fuse-able link (the one with the inline fuse see the pic below, obviously it's fused and connected to the fuse block) but it plugs into the "IGN" on the fuse block and it kills the truck i just unplug it. Where should i be looking to resolve the issue?

Thanks
Doug

Re: 78 Chevy wiring question-Truck won't shut off at the key
 

probably the switch itself or the linkage between it and the lock.