Dont put a bigger fuse in!! The amp is provided with the right protection. it will be detrimental if you install a larger fuse. Get a cheap multimeter from dick smith (10 bucks) and with the battery disconnected, test between a metal part of the chassis. (not a painted part) and the red + at the amp, on ohms. The correct reading if everything is fine, will be infinite, Open Circuit, Open Line... one of those depending on which meter you buy. If you get a reading of for example, 1ohm, the cable is touching the metal somewhere. (probably the firewall) Next, test the - screw on the amp.(the black wire) to the same spot on the chassis. you should get a reading of 0-2 ohms. If it is an open circuit, you will get a reading of infinite... see above. If the red wire is not touching the chassis, and the black one is, then you should be ok. You can also test the voltage at the amp. Meter on DC Volts, expect to read between 12-14.3V. If all of these tests dont work, take it back to the shop. It will only take 30mins to do this, as apposed to losing your car for days... hope it helps

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