Here is a link to the repair I did on my daughters GP. Same applies to MK2 Puntos, Cheap fix. Make sure the bushings in the motor are turning freely.
https://www.fiatforum.com/grande-punto/454480-heater-fan-resistor-repair.html?p=4297604
https://www.fiatforum.com/grande-punto/454480-heater-fan-resistor-repair.html?p=4297604