This is one of the products in our catalog that gets the most user errors on installation.  People connect it to the battery first, and then they let the leads flop around before they connect them to the shunt until one of them touches something negative and blows the fuse.  The other thing they do is connect it the wrong way around.

The lug goes on the positive battery post.  The two terminals go to the two small terminals of the shunt. It matters which terminal goes where, consult the manual.  Connect the shunt end first, then the battery end. The shunt battery cable has to be connected to the battery negative.  If you have blown the fuse we sell replacements.  Its hard to test the fuse because it can appear to be intact, can even test for continuity with a multimeter, and still not be able to pass current. You can momentarily replace it with a paper clip to test the system.

We get reports of these temp sensors failing but to date not one single one has actually failed, it has always been user error.