ez wiring harness

Fuses are always good. I have a bunch in that long black box in my avatar. Upstream protects more of the wiring, but otherwise doesn't matter. Since most relays are supplied direct off BATT+, an in-line fuse is very prudent (to paraphrase a former President). There is (or was) a "fusible link" (wire w/ molded tag) at the bulkhead feed on most of our cars. Groups of circuits (~6) have individual fuses in the under-dash box. I recall one is just for the lights, but that would now protect just the coil side of your new relay. Most after-market devices like radios have an in-line fuse. I bet their lawyers insist on that.