I needed to replace the small black SPST Tyco fuel pump relay. The coil was opened. Odd thing. There seems to be only two types of little black relays- 4-pin SPST and 5-pin SPDT. The two different types are easily confirmed by the numbers printed on the side of each. But...the tops sport more than a half dozen differing numbers. WTF? Are these things scientifically matched to each circuit? I do not think so.