I'm guessing that your power distribution unit (PDU) under the hood is damaged. If you plan to keep the truck awhile, you can likely find a replacement off another truck in a local salvage yard or on eBay. Once replaced, you should be able to install the correct fuse. If you want to perform a band-aid repair, you can replace the fuse in the fuse holder with one of the appropriate rating to run the lights, assuming that none of the wiring or switches on that circuit are damaged..

 

If I find one on eBay or junk yard.. I’ll have to replace the whole harness won’t I? Or just the fuse box itself? It looks like I’d have to get a whole harness. I appreciate all the help by the way! Thank you

 

I think the harness is just a big connector held in with a screw or two on the bottom of the PDC..... I think.

 

The PDC/engine fuse box are most certainly available at a salvage yard or on eBay. You best deal is to likely pull one off yourself at a pick and pay style salvage yard, if one is near you. Here's an example of one on eBay - https://www.ebay.com/itm/146214172959

You can also find them via car-part.com by searching for "fuse box (engine)". car-part.com is nothing more than selected salvage yards advertised inventory.

It would be best to take apart the PDC and see if you can perform a harness swap. I suspect you can swap the harness, but what's involved, I'm not entirely sure.

 

Ok, so now to figure out why the fuse blows. What size fuse is in there ? It should be a 20A, you could temporarily try a 25A if that blows too there is a bigger problem. Given that the PDC has issues maybe whoever put the bypass in tied another circuit to it. Are there any other fuses missing ?