Help testing a relay with no markings/

**Simon_Fuller** · 23rd May 2019, 22:48

Originally Posted by fatfred

Now I've read you first post fully i think you are correct!

Thanks mate so if I put 12v on the RED and earth on Brown it should then click?

**schplazingo** · 24th May 2019, 12:10

Yes, it should click and then you should see continuity across the other two pins. 183 ohms is about the right resistance for a 12V relay so you shouldn't do it any harm.

**Big Dave** · 24th May 2019, 12:49

You should be able to tell from the pin configurations and which way they are pointing as to what connection is for what.

See https://www.12voltplanet.co.uk/relay-guide.html for info.

**Simon_Fuller** · 24th May 2019, 12:51

Originally Posted by Big Dave

You should be able to tell from the pin configurations and which way they are pointing as to what connection is for what.

See https://www.12voltplanet.co.uk/relay-guide.html for info.

Thanks Dave, the problem is that it’s effectively sealed with no diagram with wires out the side so no idea visually where the wires go.

**Big Dave** · 24th May 2019, 12:52

Originally Posted by Simon_Fuller

Thanks Dave, the problem is that it’s effectively sealed with no diagram with wires out the side so no idea visually where the wires go.

Ah, didn't realise you couldn't see the spade connectors.

**Simon_Fuller** · 8th June 2019, 12:18

Right,

I have supplied power to the red cable that does indeed make the main relay click. I checked the voltages on the two remaining disconnected Black/white wires and neither show any voltages when this relay is active or not. I therefore not sure if the black/white cables should have 12 volts through or intended to be ground

**bonehead** · 8th June 2019, 14:55

there won't be any voltage on the other two wires, they're for the circuit you want to complete.

what are you hoping to use the relay for?

**Simon_Fuller** · 8th June 2019, 14:57

Originally Posted by bonehead

there won't be any voltage on the other two wires, they're for the circuit you want to complete.

what are you hoping to use the relay for?

Would the other two wires never carry voltage so effectively an earth?

**bonehead** · 8th June 2019, 15:14

no. the other two wires, assuming it's a typical automotive relay, are completely independent of the control pins.
they are either connected together, when the relay is energised, or not, when it's not.

**Simon_Fuller** · 8th June 2019, 15:26

Originally Posted by bonehead

no. the other two wires, assuming it's a typical automotive relay, are completely independent of the control pins.
they are either connected together, when the relay is energised, or not, when it's not.

Yes it’s an automotive really but i had two wires not connected on the relay. A yellow wire connected to loom and a black/white wire. The red and brown I know now are connected.

I now need to establish if the black/white would provide power to the yellow loom cable?