Peugeot 406 heater fan not working what do i do to fix it

If u remove the under cover in the passenger foot well, just turn the fan blower on full and hit the first thing you see when u look under the pass foot well with the palm of your hand and the blower should start to work.

I had this fault and could get it to work by thumping the motor, but the fault got worse and only rarely would it start the motor. At first I thought that the motor brushes had worn down, so I replaced them, but the fault was still apparent. Further investigation revealed that the copper 'commutator' segments on the motor shaft were very worn. Some of the segments were so worn that they were effectively open circuit, which meant that when the motor stopped (after switching off the ignition) with these particular segments directly under the brushes, then the motor will not start. However, if the motor was then hit with the hand it would sometimes jiggle the shaft around just a fraction of a degree, and this caused the brushes to re-align to adjacent 'good' segments, and hey presto the motor springs into life! Alas, as all segments are very worn, they too will soon wear down to such an extent that they also go open circuit. The only solution is to change the whole motor/fan assembly. A new one is preferable but beware of secondhand ones, as they too may have a very worn motor, so be sure to obtain one that has been stripped from a low mileage vehicle. If you cannot get a motor, then it is possible that a professional motor refurbisher might be able to strip-down the motor to renew the commutator.