I have a 2005 350Z and the heater blower fuses ( 2 x 15A) keep blowing after 10-30 seconds. Before the fuses blow I can hear the air flow surging, then faltering then surging again. I tried putting 20A fuses in as an experiment only and they blew also. The car has 120K miles and hasn't been driven for a month... I'm wondering if the fan motor is seizing up and drawing excessive current, but I'd appreciate any advice experience anyone has with this. Thank you!

 

Sounds like the issue I assume this happens when you turn the fan on in ac also?