how autonomic nervous system controls body temperature?

Answer 1

The hypothalamus portion of the brain is the body's thermostat (controls body temperature). I knew a man who was assaulted and as a result sustained damage to his hypothalamus; occasionally his body temperature would rise erratically for no reason except for the lesion; he was not ill in the sense that one runs a fever in response to a bacterial or viral infection...

Answer 2

Your hypothalamus inside your brain is the control center for a lot of things, body temperature being one of them. Sensors located all over your body alert the hypothalamus when the temperature changes and then the hypothalamus sends signals to other parts of the body to regulate the temperature (e.g. by sweating).