I'm not an expert but here is what I know about the 7 pin:
Yes, the 7 pin setup operates off of a CAN bus system (and is one of the reasons bobcat attachments are so expensive, b/c you need a controller to interpret the CAN bus signals vs something like a 14 pin connector that just fires 12v). On the machine side, you can test for 12v on the big pins at the machine connection to see if your controller on that side has 12v. Doesn't mean that controller is necessarily working but eliminates 1 possibility. You'll need an oscilloscope to read the digital signals on the smaller pins AND I'm not sure about that as I've never done it. If you look at your attachment, say a snowblower, the 7 pin on the attachment plugs into the machine and then it goes to a controller/control box. That controller is all sealed up and converts the CAN bus signals into 12v for the solenoids. Therefore after the controller can you test for 12v with the machine powered on (doesn't need to be running) and someone pressing the appropriate switch/button.
In this case it worked (I had 12v after the control box on the attachment) and then it didn't. I'll head over there tomorrow grab a few pictures and see what we can figure out. Again, I suspect either a bad connection at the 7pin, fault in the harness or possibly a dying controller on the attachment itself. But I'm not sure if a controller would work and then not.
