Formally called the Chevrolet C/K, C/K is a series of trucks manufactured by General Motors and marketed under the Chevrolet and GMC brands. The C/K line includes pickup trucks, medium-duty, and heavy trucks.
According to a quick google search, it is under the hood on the driver’s side behind the battery. A truck like this is common enough that there should be a ton of information on the web. Good luck with your repair!
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