W202 Air Condition - Cooler Level

[Lorves]

Any one can Help me ?

Recently i had my w202 C220 Cdi from 1998, rebulding the cylinder head, because of a crack.
After the repair, when i start the car, and turn the air condition on, the warning light of the cooler level on the dashboard, turns on.

The liquid is in the correct level, which makes me wonder is there a problem ?

Thanks a lot,

 

[bagman1971]

check operation of coolant level sensor could be inoperative

 

[Lorves]

How can I check it ? the cooler is in the correct level, but still i have the warning light geting on when i turn the air condition on. Thanks for your reply.