Electrical help with Prodigy Brake Controller

During a trip this past weekend, my Prodigy brake controller alternated from working correctly to showing an "NC" on the display. I have looked through the forum and the Prodigy troubleshooting info, so I know this usually means that there is a fault that makes the Prodigy think the trailer is not connected, but some of the other behavior I saw makes me think it might not be that easy. Here are all of the symptoms:

Controller flashes NC at random intervals, even when not moving at all - swaps between C and NC with no motion
When controller says NC, trailer lights still work normally (makes me think it is not a trailer grounding problem)
Even with NC showing, the manual brake lever has some effect - hard to quantify, but I'd say it is 50% effective - for example, when stopped with the TV in drive, and the brakes functioning normally, it is easy to hold the TV by pushing the Prodigy manual lever to the left. With NC flashing, the TV will not hold, but there is some braking action provided by the trailer brakes - just not as much as when there is a C showing.
With TV sitting still, Prodigy controller showed two lower bars (indicates Controller is mounted at too low of an angle). The controller is mounted just fine - this symptom makes me think it might be a bad controller

My homework so far says it's probably not the trailer ground, because if it was, the trailer lights would be intermittent - Is this a correct assumption?
So, I am left with:
1. an intermittent short in the trailer braking wires (the blue wire) - although the fact that it comes and goes when the trailer is absolutely stationary makes me think this is less likely)
2. an intermittent connection at the Bargman plug (although the contacts look clean), or
3. A faulty controller

So, my question is - Do any of you electrical geniuses have some suggested troubleshooting steps.

Thanks in advance.