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What is pin 87A for?(relay)


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I have been looking at wiring diagrams for the past few hour while doing some wiring in my car and I was having some trouble findin the pin outs for a relay that I am going to use. I am using a relay box/fuse box out of some kind of Dodge product(not sure on what kind of vehicle because I got it out of a pile of old wiring harnesses from work). Now it has 2 spots for your normal square relay and 2 spots for those smaller relays(I think they are called micro relays?). Well I think I found the info I need on the pin outs but I have one question that I just cant seem to answer by myself....

 

What is pin #87A for? It seems like it goes to nothing in all the wiring diagrams that I have but why put it there if it just goes to nothing? Do I need to hook it up to something?

 

Thanks,

 

Guy

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Ok I think I may have answered my own question...

 

After staring at some more diagrams, I think that the reason there are two 87 pins(87 & 87A) is because 87 is set up for a circuit that is normally open(the contact rest on 87A) and 87A is set up for a circuit that is normally closed and when the cicuit/relay is energized it opens the contact.

 

That's my theory but is it right?

 

 

Guy

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If it helps--yes, you did answer your own question; one is NO, the other is NC.

 

Be careful when buying replacement relays as well--some of the ones they sell for lighting setups appear the same (have all 5 terminals), but there are really just 2 87 pins, no 87A

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Well thanks for conferming my theory. I went ahead anyways today and wired up the relays that I needed to and didnt use the 87A for anything. I was pretty sure I was right and Im glad I was because I am getting a little burnt out on wiring. Although I should be about 95% finished by tomorrow afternoon with wiring up my new engine harness!

 

Guy

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