[PaulD]

Amps go into protect mode because 1) short in ther speaker wires 2) DC offset in the output 3) overheating. I can assume it's not overheating since it does immediately. Try taking just the box and connecting that to a friends system and let it rip for a while. If your subs work fine, try his speaker box in your car and see what happens. One of those scenarios should work fine and the other should cut out.

P.S. sorry, you posted this after I had checked it yesterday.