Duo Therm 5 button Tstat does not "see" new 2nd AC unit

[sparky6156]

I have downloaded and read everything on troubleshooting I can find from Dometic/Duo Therm for this set-up. I have cleaned communication jacks and cable ends with electronic cleaner, replace the communication cable ends from AC unit 1 to AC unit 2 with cable orientation to cable ends as detailed in troubleshooting guides. I have replaced the control box on the original unit, reset the Tstat multiple times and verified DC polarity at control box connection to RV DC supply (13.84 VDC). At the RJ 11 jacks, there is no DC voltage from Red to Black, (which is not what is expected per troubleshooting guides) but there is 12.75 VDC from Red to Green and 4.74 VDC from Yellow to Green when reading through the communication cable plugged into a standard household phone jack. The communication cable looking from left to right with the locking tab on the connector facing me is Black, Red, Green and Yellow on both cable ends. The original AC and furnace both work as expected, but the 5 button CCC thermostat does not show "zone 2". The RV was prewired for a second AC unit with a remote temp sensor preinstalled as well as a 20 Amp 120VAC supply circuit and a preinstalled communication cable. Dip switches on second unit are all off with the exception of Zone 2 (turned on) and all off on the original unit with the exception of the furnace dip switch (turned on). Please help, as I only have so much hair left; and what I do have is hard to get ahold of to pull out!

[dougrainer]

sparky6156 wrote:
What will be the simplest way to verify the RJ11 jack configuration on the circuit board?

There is NO reason to worry about the pin alignment on the Circuit Board. Doug

[sparky6156]

What will be the simplest way to verify the RJ11 jack configuration on the circuit board?

[dougrainer]

ALL 5 button boards are the same. ALL 10 button boards are the same. The difference is very obvious, so you should be able to tell. Also, you are assuming the COM cable from Zone 2 to Zone 1 is wired correctly on the modular plug from the factory. Have you verified the Wire alignment for the plugs? Doug

[sparky6156]

I installed a Brisk Air II (579 series), and when I ordered the control box, I told the tech person the unit I needed the board for.
I replaced the factory installed control box on the original Quick Cool AC unit (Zone 1), only to find that was not the problem. I plan to install that (working) original control box from AC unit 1, to Ac unit 2 tomorrow.

[Mandalay_Parr]

On mine there is a DIP switch on the front AC board that tells the system there is a 2bd AC in the system.

[dougrainer]

State the Model AC you installed. IF you installed a Penguin Model(600 series), of course it will not work. The onboard Penguin Control board only works with the 10 button wall CCC unit tstat. If you want the new AC to work and it IS a Penguin, then you have to purchase a 10 to 5 button retrofit control board kit. If you purchased a Brisk Air model(500 series) and then had to purchase the control kit and did NOT specify the 5 button kit and purchased a 10 button kit, then that is your problem. You CANNOT mix 5 button and 10 button control boards. Doug

[Twomed]

You do not mention a thermostat reset. That must be done to "see" the new unit.