Heater Blower fuse keeps blowing

Hi, 

I've got a Skoda Octavia 1.6tdi 2010. 

A few months back the 40amp fuse for the blower blew so I replaced the fuse and a few weeks later it blew again. 

I checked on here and there was a lot of comments about faults with the resistor pack so I replaced this and again all was fine for a few weeks until the fuse eventually blew again. 

Checked again on here and it said about the motor so I replaced that and again all was fine for a few weeks and then the fuse blew again. 

Took it to an auto electrician he said the motor was sticking and checked how many amps the motor was drawing and said it was just below 40. 

I replaced both motor and resistor again at the same time and low and behold the fuse has gone again. 

Does anyone have any experience as to what may be causing this? 

Many thanks in advance