Noobie - why is my 12V relay not firing?

[blindesp]

Having a hard time trying to get a relay to work, looking for some guides.

I am trying to follow this as attached and here https://esp32io.com/tutorials/esp32-controls-pump but brand new to this and not getting my pump to fire

- Pump fires from direct connection to a battery fine (12v 7.5A) ok no problem
- SRD-12VDC-SL-C relay wired up to ESP32 and coded to switch on relay on/ off every few seconds and leds light up to indicate it does ok
- 3.3 voltage read ok from esp32 to relay on the DC- and in
- 12V read on the output side of relay but no firing pump ( i have it wired on com and no )

brand new relay, seems ok but I am not sure if i have the right relay? The relay reads 12V 10A so assuming this is man enough for my pump. Assuming i have wired or done something wrong?, any pointers, or guides? thanks

[blindesp]

Also to say here the relay output is :
- Com to Water pump positive
- No(normally open) to 12V power adapter positive and negative of power adapter to negative of the waterpump

I assuming normally open as when i connect power directly the pump spins up.

I tried moving the nomally open to normally closed but the pump just stays permanently on and the relay has no affect. If i try and research this i end up doing full blow electronics courses. (also tried scrapping the power splitter and use a straight connection block to no avail ( i was hoping to power a 12v solenoid valve as well.

I think my wiring setup is wrong as the ESP32 and Code looks good, I "Think" the relay works, its new, is the wiring diagram i am working off incorrect? most probably something stupid I am doing but really struggling to get my first ESP project off the ground. The pump is 12v 7.5 so I am guessing here because the relay is 12v 10A this bigger Amp number is bigger than 7.5 and would therefore work?

First person to respond gets a free "your an Eejit" token

Thanks

[arc12_esp]

I suspect you have misunderstood the "12v" designation for the relay. I would expect that to be the relay coil voltage. If you are supplying it with 5V, there will probably be insufficient "pull" from the relay coil to close the load contacts.

Can you hear the relay "clicking". It should be strong. If not:
A) Get a 5V relay module and make sure the relay module gets 5V, not 3.3V for its supply (the modules usually work on 3.3V logic, but need 5V power supply).
B) use your 12V supply [presuming it is DC] for the relay module, ensuring the ground/0V for the USB 5V and 12V supply are connected together.

[blindesp]

ok, i think i cracked it, reading back through comment, getting out multi meter and researching into relays......i was using the wrong relay.

not understanding relays i though a 12v relay was for the output, but the esp outputting at 3.3v and inputting into the relay was not enough to fire it, a 5v relay was enough to be triggered and whole setup works, I am learning slowly.........