Peugeot 307 HDI temperature board problem

Temperature board problem - Pointer for temperature gone crazy, when I turn heating to max and air flow to max it got stabilised, fans wasn't turned on and temperature of environment was about 30C, and the car was going uphill.
Its not on video but, when put key in keyhole and turn it for contact, pointer for temperature go to maximum and than it come back to ordinary position, I assumed that its normal (like calibration) but its not like that on other cars...