C350 w204 loud fan noise

[Iainc350]

Hi all,
I have a Mercedes c350 which at the moment occasionally tje loud fan noise kicks in and the temperature gauge does not move?
Then switch the engine off and on and again and it's gone???
No fault codes at car garage.
Only thing it's going on to have done end of week is a new bulb holder rear of car as this appears to flash up as all different bulbs. Wired have melted.
Could this have anything to do with it?
As the last time the other side went it played around with the system such as abs playing up.

Thanks

 

[C350Carl]

Is it a petrol or diesel?

If it’s a diesel it will probably be a DPF regen. Do you notice a lot of heat coming from under the car when you get out?

 

[Iainc350]

Had the lights rewired.
New circuits too stop
Over heating.
And coolant sensor is what needs changing?