The fuses all seem intact, the cigarette lighter is working fine, but the accessory socket is giving nothing. When I put a DVM on it (or rather, the wires on the plug at the back), the voltage crept from 0 to 5v slowly, which I'm guessing is capactitance somewhere.
Any thoughts on what's likely to be bust?
I'm tempted to wire it off the cigarette lighter for now...