To help you find what you need, please clarify:
* What is the purpose of this cord? Is it related to a sensor (like a knock sensor, coolant temperature sensor, etc.)? Is it a ground wire? Part of a larger harness?
* What are you trying to do? Are you trying to repair something? Replace a sensor? Knowing the context will help.
* Can you describe the cord? Color? Size? Any markings? A picture would be extremely helpful.
With more information, I can give you a more precise answer or point you to a wiring diagram. You can find wiring diagrams online through sites like autozone.com or by searching for "1998 Chevy Blazer wiring diagram" along with the specific component you're working on.