Yes, it can be blown. To check a fusible link just check for voltage before and after the link. If you have voltage before, but not after the link is blown. You can also continuity test them with an ohmmeter, not always accurate though.
you can check for continuity with a multimeter.usually you can pull on the fusible link and it will pull apart because wire holding it together is melted leaving only the plastic/rubber coating.but the best thing to do is check for continuity with a digital or analog meter with a few sewing needles for penetrating plastic/rubber coating and then place meter terminals to needles to check for continuity and when finished use a waterproof sealant and wipe over needle hole to seal hole and replace with same size fusible link (very important) they can be purchased at any auto parts store.
A blown Fuse links can be difficult to trace but once you do find it, replace it with an inline fuse. That way when you reapply power to the system and it shorts out cause of a hard fault you can quickly find the prob and easily replace the fuse when once you fix it. Just remember to use the correct inline fuse for the job. Watch your wire gauge and fuse amps when installing off the shelf inline fuses
Fuse links come with a current rating just like fuses. A clue as to what current they are designed for is to look at the size wire they protect. Here's a table:
Keep in mind that the wire size in the chart is for the circuit itself, not the size of the fuse link. The packages of fuse link repair material you can get at the auto parts stores also will have a current rating on them.
Aircraft type circuit breakers are designed for low voltage DC applicaions and would be an excellent choice to replace fuse links. They come as a push/pull to reset button, and range from 1.5 amps to 60 amps and higher.
There is a store local to Orlando that does electronic surplus and has all kinds of circuit breakers. See www.skycraftparts.com That's where I get most of my wiring supplies. There may be a similar type store in your area.
Jrichker is right on about replacing links with CB's as they need replacement. I think JR and I both had plans to get rid of the links and install underhood fuseboxes, but I know I (for one) never got around to it.