What does a relay do in a fuse box?
What does a relay do in a fuse box? Relays control a high-current circuit using low current. It makes it possible to control things like the headlights and the fuel pump without running high-amperage current into the passenger compartment. Try swapping the relay. Remove the relay from the fuse box -- It pulls straight out. What are the terminals on a fuse box? Look at the terminal labels on the relay. They are identified as 30, 85, 86, 87 and 87a, if it is a five-terminal relay. Terminal 30 receives constant battery voltage. Terminal 85 is the relay's connection to...