When the ECC fan is set at zero I thought this was supposed to turn the ECC system completely off, regardless of the temperature setting. I have this crackling sound (kind of sounds like a computer cycling through its stuff) in the dash behind the ECC unit. The noise doesn't stop in positon two or one of the key but stops immediate when you take the key out. Is there anything to worry about here other than the noise. I don't want to replace the whole ECC unit since it seems to be working except for this.