Faulty instrument panel Mercedes benz s310 1994

[warr]

The section of my car's instrument panel that displays the car's temperature is malfunctioning. It does not displays a constant temperature and instead moves up and down drastically. I was wondering if anyone knew a fix to this? Can this part be bought separately or do I need to buy the whole instrument panel? The sensors were replaced recently so I doubt that is the problem. Anyone know where I can buy the panel from?