Hi Steve, I presume,no error codes,bleeps,lights etc.
If not, it is more than likely the recirculation motor.If it has filled,and you listen closely,you may hear a faint humming noise.
The part numbers are:
Motor 481236158434
Fixing kit 481231028375
It is a different motor hence the fixing kit but a much better one.
Any more help please ask.All the best.
Foxy, July 2008