[SentraSE-R]

FWIW, I believe Brucepick's explanation of the fuel injector relay in message 9 of this thread is incorrect. Most automotive relays are either four terminal (as he described) or five terminal. Both four terminal and five terminal relays connect the two "switched" or "power" side wires in Normally Closed (NC) position by default. This is a fail-safe mode, so if the relay fails (its triggered electromagnetic contacts don't move), your fuel injectors will still work when untriggered. When you power the "control" or trigger side terminals, you open the "switched" or "power" side circuit. In a four terminal relay, the switched/power side circuit opens, and there is no continuity - the opposite situation to what Brucepick said. In a five terminal relay, the same thing happens to the switched/power side NC terminals, but the fifth NO terminal connects to one of the NC terminals, so you make a connection between those terminals in the switched/triggered Normally Open (NO) position.