first of all, never disconnect the load (i.e. speaker) when the amp is on and playing music. you might well blow something that way. anyway, about the wattage, you can't measure watts off of a speaker (reactive load), you need to use a big power resistor (called a dummy load) and measure the voltage across its terminals to get VRMS. as for the actual amplifier, if you post some pics of the wiring, that might get you somewhere.