thanks for the replies and suggestions guys!
So hereís an update
(I liked Fridge Defends bulleting his reply comments- so I per bulleted mine in the event anyone wants to reference a step)
1) The Norcold N8X was run on shore AC power with some water bottles in both compartments and I put an indoor/outdoor thermometer in the freezer section with the outdoor probe in the fridge.
The only way I can tell if the AC is cycling on or off is by the 3amp increase or decrease on the load panel in the MH. Periodically checking that- I do see the HM load swings +3A/-3A from time to time. If I open the fridge door- in a few moments I do see the load go up by 3A.
Nothing else is powered on except for the Ďdeadí draw the MH has when house batteries are on.
2) After 12 hrs the freezer temp was -9 and fridge was 34.
Outside the MH ambient air temp was 79 and inside was 82.
3) I hooked up a VOM to the gas solenoid in hopes to capture any high/low voltage to the solenoid to indicate that the gas was cycling on/off.
I unplugged the AC shore power and the gas burner kicked in.
4)Voltage on the gas solenoid was 12.4vdc (house batteries are at 12.6), and I set the VOM to capture High & Low readings. This way- currently both are reading 12.4 but when I come back later if I see a low reading of 0v Iíll know that the gas did cycle off at some point.
5) 6 hrs later I checked the temps in the fridge and the freezer went down by only 1deg (now -6), and fridge went up by only 1deg (now 35). Ive never seen anything more than +/- 2deg change.
6) The gas burner never shut off- I never heard or saw it go off, and the low reading on my VOM never went to 0vdc.
7) Interesting thing though- my VOM high and Low were both reading 10.79vdc on the solenoid, and 11.6vdc on the control board. (Batteries were still at 12.6) Readings were taken from the signal + and - connections as well as signal + to ground.
I retired from 45 years of working for a major Automation Controls manufacture (Allen Bradley/Rockwell Automation) as a systems/Controls Eng and service Eng- and to me-
8) that sounds like some load or resistance has increased or changed between the battery and the control board. And I know at those low DC voltages thereís a risk that not all electronics will operate efficiently / correctly. Current demand (Amps) shouldnít knock down the Voltage level, to me thereís a resistance or load increase between the batteries and Control board- or a component breakdown in the control board.
9) Could something on the control board (i.e. capacitor) be heating up (via current) and failing causing a bleed to ground? (causing higher load?) Where would this extra load / resistance be coming from? House batteries are holding at 12.6
10) I checked, cleaned and reseated all connections.
11) When I plug shore power back in and the unit goes on AC, the Control board voltage comes back to 12.6 and stay there all the while on AC power.
12) I unplugged the AC again, the Voltage on the Control Board and Solenoid was at 12.4 and I had to leave for a 3hr errand. When I returned, the gas was still burning and the voltages were again 10.79vdc on the solenoid, and 11.6vdc on the control board.
13) Still havenít ruled out the suggestion of a dirty flue/flue baffle as I can understand the heat transfer problem- but how do you remove that and get in there?
14) Other than that- Iím thinking Iíve got a flakey control board. My wife mentioned to me that occasionally the unit wont Auto switch over to gas when the shore power is unplugged. (thatís news to me! Iím outside unplugging it and when she seeís the switch over fail she manually turns it to gas. Thanks for that late tidbit!
Thanks for all the help- this site is my go to place to find answers from real users, or to just get a heads up on fixes before the problem shows up!