Jim, I have the exact same model. Luckily the State of Florida purchased it, and it was not my own money. I too have been very disappointed with this POS. I never read the instructions for it...It only takes a tiny bit of common sense to hook one of these things up properly. But now a days, it seems everything has safety features and it made to be what I call "dummy proof".
That being said, I'm convinced that this model is equipped with some sort of safety feature that prevents current from being sent to the cables when they're plugged in, until it's ready to be used. I've attempted to jump several pieces of equipment, including ATV's, trucks, and boats with no luck. My theory is, that it must sense some sort of voltage in order for it to kick on. In other words, if your battery is nearly dead, or completely dead, you're SOL. Isn't that the reason DO NOT WASTE YOURE MONEY ON THIS PRODUCT!!!
After writing this response I decided to do a quick YouTube search. Here's an instructional video on how to use it. https://youtu.be/q7xWhyr-dDI