Mach Dual Zone, Zone 1 reads 41 deg

[chaps2018]

Hoping one of you smart guys have some experience that can help with this situation;

My configuration:
-Mach 15k and 13.5k AC with gas furnace
-No HP, no heat strip
-Dual zone thermostat
-Zone 1 temp sensor is local to the Tstat
-Zone 2 temp sensor is remote.

Notes:
-Zone 2 works as expected
-Green lights ON both upper control boards
-System has worked fine for the past 2.5yrs
-No new installations or changes to the trailer
-Thermostat/system responds normally to all commands except for symptoms below
-Fan controls operate as expected on both AC units

Problem: T-stat not reporting accurate temperature in zone 1. It displays 41deg (default minimum temp for the system per the manual). For a couple of days it slowly alternated between the accurate temp and 41deg then finally now just says 41deg constantly.

Symptoms:
1--When switched ON via T-stat, the furnace runs constantly. This is due to the zone 1 reported temp of only 41 deg. Setpoint 70deg, Actual temp in the room is 75deg in the test case.
2--When switched ON via T-stat, the zone 1 AC will not turn on. I believe this is due to the t-stat reporting a ambient temp of 41deg and set point is 78.
-----Note on symptom 2: for a couple days the Zone 1 temp slowly alternated between the actual room temp and 41 degrees. The zone 1 AC responded appropriately while set to AUTOCOOL and setpoint called for AC.

Steps I have taken to resolve the issue:
--Verified each connection from t-stat to Gas furnace. Found many loose connections in the basement and recrimped with new lugs. No change problem or symptoms noted above
--Verified each connection from t-stat to Zone 1 Upper control board. No loose wires.
--Replace T-stat: no change in problem or symptoms above. Verified programming and all systems operate with the exception of the symptoms noted.

I have been unable to find a troubleshooting guide from Mach on this system to take the next steps.

Equipment list involved here
Furnace: Atwood AFMD30121
Main AC unit: Coleman mach 15 model number 48254c869
Main Upper control unit 9430A751 Zone Control Kit (12vdc cool only)
2nd AC unit: Coleman Mach 3 Plus model 48203c969
2nd Upper control unit: TBD
Tstat: RVProducts(Airxcel) 9330A334

Thanks in advance.

[chaps2018]

Originally Posted by chaps2018

Main Upper control unit 9430A751 Zone Control Kit (12vdc cool only)

SOLVED: it was the control unit in zone 1

Temp In zone 1 now reading correctly. Also had to reprogram (took less than a minute) the control unit via the thermostat.

Hope this post saves someone grief in the future.