hi all can anyone help?

keeps blowing the fuse on the resister, done the mod and put a new fuse on but still it keeps blowing it!!

Rang Vauxhall and they said they donít know of any issues with this problem and the only way to check the heater motor is to spin it by hand and if it feels free its ok, next is to check the drain isnít blocked and there is no damp getting in around the resister, done all this and still canít find the reason,

any suggestions????