NH grain loss sensors faulty

[Traktaris]

After winter both of straw walkers grain loss detectors stopped working. Combine is CS, but probably the same as CSX and older CX5 and CX6 models. Error codes are E405 (left hand straw walker grain loss detector open circuit) and E408 (right hand straw walker grain loss detector open circuit). I don't think both sensors would go at the same time. How do you test if grain loss sensor is faulty? I checked wires from last plug to sensor to the bottom of the cab and it seems there no wire breaks or shorting to ground.
I would like to learn to test if loss sensors are faulty and if they are OK I need suggestions what to check next

 

[Badshot]

Mice

They are every bit of insulation off my yield meter, knackered it as it was right up to where it disappeared into the metal sensor.

 

[Traktaris]

Update. It's 2 wire sensors so I disconnected sensors and shorted blue and yellow wires and now error changes from "short to battery voltage" to "short to ground". I believe this means that wires are OK and that both sensors themselves are faulty?
Also I am not sure if the term is actually 'short circuit" or something else, my operators manual is not in English, but I believe it would translate into English as "short circuit".
One fault would translate as short to ground, another as short to battery voltage