Arduino Mini freezes when display connected

Hi, i using arduino to control water pump. When display is connected it freezes sometimes. I have 2 different lcd displays and with old one it works longer without freezing, but with new one it freezes very often. I measured resistance and there is difference between these 2 lcd's even they looks same, except few details on i2c serial adapter.

I noticed that when arduino is on and if i disconnect and connect new display it restarts arduino, and old one doesn't do that, so i soldered few resistors between vcc and all other pins on i2c serial adapter and after that it worked longer without freezing and didn't restart arduino.

But, it still freezing more often than old one. I connected old one and left it overnight and it freezed once. Without display it works without freezing.

I have no more ideas, maybe i should put resistor on sensor pins, but how to connect it?

It is worth putting a small (incandescent) light bulb in the pump enclosure. This will stop the pump freezing in cold weather. Impeller pumps with cast iron bodies are very susceptible to frost.


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When you stage it freezes sometimes, I assume you are saying it does not work and what is being displayed does not change. Or are you physically talking about it getting so cold it freezes it mechanically, in which case it will not last very long. If it is not being mechanically frozen please post your schematic, not a frizzy thing including links to the technical information on the hardware items.

So the freezing happens with both displays. It sounds like interference from the pump causing interference with one of your displays being more susceptible to interference that the other.
Apply a good dose of power supply decoupling and even a capacitor across the motor bushes.

I thought arduino freezing, system freezes and not responding. Btw, i soldered 2 4k7 resistors instead of 10k between VCC - SDA and VCC - SCL. Now it works 3rd day without freezing, i noticed that display sometimes goes crazy and show some unusual symbols but that's not problem for me since program works and do it's job.