sure, i think this is how you want it...?
As for all the hardware:
LM35 sensor
arduino uno
2n2222 transistor
12V DC fan
16*2 LCD I2C
1kohm resistor and a 220Ohm , 10 microfarad capacitor
1n4007 diode, LED
12V DC adapter
Also this might be helpful but i was using a 12 V AC adapter instead previously, and the fan and lcd were actually working yesterday but only for a single run, after that they both died. The lcd i believe i accidentally messed around with one of its wires whilst it was powered on , and for the fan i think the AC adapter may have had something to do with it, although the DC adapter being fried afterwards still confuses me.
Also, I'll try out your suggestions with powering the LCD in just a moment.
Edit: THE LCD IS WORKING NOW???!!! ILL TRY AT IT FOR A BIT AND SEE IF IT WILL FINALLY WORK!!
EDIT 3: good news, temperature sensor works! bad news... i might be a little uncertain on my final fan circuit... will upload the picture of the final circuit on another reply in just a minute bc of the 3 picture limit:
