Is there some way to test the 12V connection on the unit directly outside of the sled? Or even in the sled with connectors to wires?

Yes. If you simply want to test for the presence of 12 volts, a simple 12v light-bulb tester will work, available at any auto parts store. If you want more detailed information about the connection (current, voltage, resistance, etc.), then a multimeter is necessary, available at any Radio Shack. I have a pretty nice digital one...

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Tony Fabris