# On car relays the ones with 4 or 5 pins how do tell if they are normally closed or normally open.

I know they have a little drawing on them but how do you tell by the lines on them.I know one if you give it volts it will not have any resistance,and the other will.Does anyone know?

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There may be symbols on the relay that will indicate NO or NC. The only other way to tell is if you buy the electrical repair manual for your car. The information in the schematics will show NO or NC. Taking the relay and testing it will tell you what it's doing right then. Using a DVM and testing continuity, if it's unplugged and and testing across the legs it shows all zeros it means that the circuit is complete and there is no resistance from point A to point B, but once power is put to the relay, if the same legs now show resistance (Numbers jumping up and down or anything other than zero, then your circuit is open.

Posted on Dec 13, 2014

Testimonial: "What I wanted to know on the relay itself how can you tell by the diagram if it is a normally open or normally closed"

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Posted on Jan 02, 2017

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