Before further testing, I would like to add two driver area indicators that may help.
1. The dash console analog diesel battery meter does not function until the key is switched ON. Once ON the meter reads below normal, which would be the midpoint (or twelve o'clock) position. When the alternator begins charging the indicator will move to slightly above normal. The meter ranges from 0 to 18vdc with only a midpoint scribe line for Normal (no numbers other than the zero and the 18).
2. Also there are level panel indicators for the diesel batteries that are 4 vertical mini-lamps that when lit go from red (discharged), red & yellow (below normal), red & yellow & green (normal), and finally red & yellow & green & green (charging).
My indicator lights with key off are usually red & yellow, going to green or double green when charging.
The diesel battery lamp goes to red with key switched ON and stays there even while driving.
I hope this makes sense :h Thank you for your patience and help. I will continue next week after our Easter celebration.