Thanks for the input,I never had a diesel MB with those fans actually starting,the gas engines get hot,diesels are running cool,however,here next to WI/IL border with mostly hwy traffic,temp rarely gets above 90,even at idle in the summer,so,I will disconnect them till I find the source of the problem.The AC does not work either,with the system fully charged and new ACC and new vacuum lines,done last year by the PO at a fenomenal cost,I belive those problems are related somehow and the coolant sensor is good,fans are on high all the time,with the sensor disconnected or not.