relay controller from temperature sensor

i am trying to make a standalone fan controller that requires no input as i am trying to add electric fans to my vehicle and would like to have alittle more accurate control than just on and off with a regular switch any help with programs or code would be appreciated i suck at coding

I think just have a device where if it hits a trigger point you specify with a potentiometer it stops the fan, otherwise it keeps it on, all of that with a relay.

Very simple to make, and even simpler with arduino

I would suggest that you take a look a Raspberry Pi Pico or a Arduino. The "requires no input" makes no sense to me as the strength is that you can add sensors (temperature, light and engine started) and a control device as potentiometer or as Í prefers "rotary encoders".

And I would stear clear for relays and rather use a MOSFET module, example https://core-electronics.com.au/freetronics-n-mosfet-driver-output-module.html

no input as in i don’t have to interact with it at all as soon as the pi is turned on i wont have to touch it it just runs it code

i would like it to come on at low speed at 150 degrees and high speed at 190 or 200 and turn off after a certain speed or temperature is reached

Then you have got answers that cover your question?!