Stereo Exhaust Fan - Cool

[JLR]

As luck would have it, it appears that the tiny exhaust fan on my bridge stereo head (Clarion CMD4) is either out of balance or about to die. Unfortunately, I found this out when I heard the fan running, with the stereo head power off, just before I was about to fly off for one month. So, I cut the wire to the exhaust fan so that I would not have a major problem while I was away from the boat. The breaker for the stereo did not shut off the fan. Here are my questions for the stereo gurus out there. Frankly, my days of installing car stereo head units are long behind me. First, since the head unit is mounted on my bridge with the entire under side of the bridge behind it, how necessary is this little exhaust fan to begin with? Second, why is the fan running even when the radio is off. The answer is because it is supposedly wired to a non-switched source to maintain the memory of the head unit. Thus, I do not know whether some relay inside the unit failed to shut off the fan or, it has been running forever and only now makes a noticeable noise since it is out of balance. Either way, I have bought a replacement fan (shipping now from Malaysia) but frankly would prefer simply to operate the unit without the cooling fan given the very large space behind it. Is this possible? Lastly, since the fan does run continuously with the unit off, is it more likely a problem with the unit itself or the fan? Sorry for all of the silly questions but I am reluctant to exacerbate a problem if I do not need to. And, to answer the obvious question --- I have no idea whether the fan has been running for the past two or three years that I have owned the boat. Thanks for the help.