Power to Dosing pumps causing Arduino reset

hey folks looking to get some help on my aquarium dosing pump project. I am soo close to being done but I cant seem to figure this one issue out.

I have an UNO hooked up to a 8CH relay module, driving 12v generic ebay dosing pumps. everything code related works flawlessly relays firing at the correct times etc.. until I power up my 12v source, as soon as any of the dosers get power it resets my Arduino.

I've done some trouble shooting all components have separate power sources and I've tried adding a 1N4001 across the motor leads

Please post a wiring diagram (hand drawn, not Fritzing) and links the motors, motor drivers and power supplies.

jremington: Please post a wiring diagram (hand drawn, not Fritzing) and links the motors, motor drivers and power supplies.

here are the motors ( I wish I had more details on them) https://www.aliexpress.com/item/1Pcs-Lab-Water-Analytical-Liquid-Aquarium-Lab-Chemical-DC-12v-D4-Dosing-Pump-3mm-Peristaltic-Head/32636884799.html

I am not using drivers, just controlling them through the relay.

power for the Arduino is a USB power bank 2A, the relay module im driving from a 12v-5v buck rated at 750mA and the motors im powering with a 12v SLA battery for now.

I will work on getting a diagram, but its really a very basic setup

You know, of course, that many USB "power banks" shut down when the current drawn drops below some minimal level, and that minimal level can be higher than the current drawn by Arduino itself.

Have you connected all the grounds? That is why we need to see a wiring diagram.