I pulled a relay box from a ford truck at the JY. The relays have 5 studs, 85, 86, 87, 30, and 87a. What does 87a do? Also it has some smaller relays, that are half the size, and they have a stud pattern like this:



I I I
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They are numbered 1-5 instead of 85-87, 30, but from looking at the side they have the same scematic on them with different numbers. Can I use these smaller relays the same way os the larger ones?

 

87a is normally closed. Thats where it rest at.

 

 

That is the answer to your question.

That is a SPDT relay.

Pin 87A is the normally closed pin. If you wire it up like a normal relay, then you want to use pin 87 as your "power to accessory" pin. When you trip the switch, the relay will go from pin 87A to 87. When the switch is off, pin 87A will have the power to it.