Everytime I start my 2002 Range Rover the sub-woofer makes a clicking noise as if the amp is giving the sub some power but the sub-woofer does not work. When I am driving or even at a stand still the clicking continues and occurs every 5 minutes or so. What could be the problem? Should I buy and new sub-woofer and amp set or could it be an wiring problem? I would just go to a dealer and have them check it out but, because I am in the military stationed in Sicily there are not many options on this island. Please give me some insight. Thank you for your time in advance.