'99 2.0l hdi 406 internal air circulation fan

check the 3 relay switches behind the grille.... if one of them is faulty the symptoms you described occur. otherwise diag2000....

If that checks ok, then check if its fed from an aux contact on the ignition switch....They stopped doing this at around 98/99 I think. Had to change the ignition switch on my late 98 406 for the same reason.

thanks for the reply.

Funnily enough, the fan started playing up on Wednesday in Stratford. I drove home on Thursday (350 miles) and the key would not budge. Could not turn the engine off or anything. But twisting the key did have the fan clicking on and off.

The car is now in the garage (local mechanic who does all my work) and waiting on a new set of locks from Peugeot which wont be for a few days... but I will let you know the outcome.

Thanks again for the reply - I appreciate the advice.