relay module refuses to work.

I bought this particular relay module for a project I’m working on:
[url=http://</url><[8 channel relay module](

This thing perplexes me. After having assembled everything, I found that none of the relays have any continuity when on.
The LEDs turn on, the relays click but the contacts don’t close. I tested everything with a multimeter, the NC terminals open when the relay activates but the NO contacts don’t move. I’ve tried powering it via the arduino itself, and from an external 5V supply. I’ve tried connecting only one relay at a time with all the same results. And all 8 relays on the board do the same thing. The only thing that makes sense to me is all 8 relays came from the same defective batch. What do you guys think?

Any help would be greatly appreciated.

fixed link:
8 channel relay module

Are you checking from Com to NO when the relay is energized? The click you hear IS the contacts, ad there is only one for a single pole relay.

No, i'm checking across the relay contacts. The relays on this board are SPDT. The relay clicks, the NC terminal opens, but the NO terminal doesn't close.

What is the ampere rating of your 5v source

Need to check from COM to NO or COM to NC, not NO to NC


Then that's your problem. When energized the contact is between Common and N.O. It sounds like you are measuring between the wrong two terminals.

I figured it out. The terminal diagram silk screened onto the board isn't very clear. Awesome chinese quality