* Location: It's typically located under the hood, often on the driver's side fender apron or inner fender. Sometimes it's in a metal box, other times it's a more exposed panel.
* Appearance: Expect a rectangular metal box or panel with several fuses. The fuses themselves are likely the older style glass fuses. There might be a cover over the fuses, but it may be simple or even missing if the truck has seen a lot of use. The panel will have a legend or diagram either printed on it or attached to it, indicating what each fuse protects.
* Size & Number of Fuses: The box will be relatively small compared to modern fuse boxes and hold a relatively small number of fuses (likely less than 20).
* No Standardized Appearance: Pictures of 1978 K5 Blazer fuse boxes online show some variations in shape, size and mounting. Finding an image search with "1978 K5 Blazer fuse box" or a similar query alongside pictures on sites like eBay of parts for that model year could give you the best visual representation for comparison.
In short: it's an older style, relatively small, metal fuse box with glass fuses. To know precisely what yours looks like, the best bet is to look under the hood of your own 1978 K5 Blazer. Or, search online for images using the above search terms and compare.
