Peugeot 207 SW heater blower stuck at full

My dad has a 2010 Peugeot 207 SW & last week the heater blower stopped working completely. We checked the fan itself & confirmed that was working so concluded it was likely the resistor so a new one was ordered & that arrived today, However with the new resistor installed the fan motor is stuck at 100% & while the display changes when buttons are pressed to alter the fan settings the fan itself remains at 100%.

I took the resistor off again & noticed that the heat sink was red hot so am thinking maybe the new resistor is faulty (It is an aftermarket one as he said he had issues finding one that wouldn't take a month or more to arrive for some reason) but just want to see if there's anything else I should look at before sending it back.

This is what the heater control panel is like if it's relevant.

Thanks for any help.