Roof Top AC Control Board Question

[Farqs]

I have a 2004 Newmar Kountry Star with 2 roof top AC units by Dometic. I am having problems with the rear AC unit not working. I have completed a lot of trouble shooting and found that the telephone style cable from the Comfort Control Thermostat has 1 bad wire in the cable from the front AC board to the rear AC board. This cable is running from P2 to the P2 socket on the 2 control board.

My question is, what is the purpose or were does the cable from P1 on the rear AC control board go to.
P1 on the front AC unit connects to the CC Thermo, P2 on the front unit connects to P2 on the rear unit.

My second question is, the Dip Switches. Front AC control board, all set to OFF except no. 5 FURNACE is set to ON. On the second unit, all are OFF except no. 2, ZONE 2 set to ON. From what I have read, this should be the correct settings.

Thanks for any help.

[Skip426]

Welcome to iRV2. and the Newmar family.

Sounds like you've gone way deeper into your AC issue than I've ever had to , so I can't offer much in the way of help. but maybe some ideas.

Dip switch setting , should be to help the AC units decide which responds to the zone 1 and 2 outputs from the CCC thermostat and the cable between the units would be to stagger the compressor cycle start up , and by doing so avoid overloading the electrical supply.
I've seen a post on , replacing the cable ends , to repair the continuity issue you describe , I'll see if I can track it down.

Is your CCC thermostat a four or five button unit ?

[Farqs]

Thanks for the response.

I have a tool to replace the cable ends. The current end is on correct, but the green wire fails the continuity test.

I have the 5 button unit. On reset, it came up "EE" error code for communication error. Nothing worked and when I disconnected the 2 cables on the rear AC control board, the front AC and furnace works fine.

I will have to replace the phone cable P2 connecting the two CA control boards. Will not likely be able to fish the wire through so will have to lay it on the roof and glue down.

I was curious as to were the P1 line on the second unit goes to. There is no continuity from it found anywhere else.

[Magredvet]

Don't know if it's the same on your coach, but I was told the second comm cable, on my last unit went to the auto gen start.
If you have a ducted setup, the easiest way to run a new cable from unit 1 to unit 2 is through the duct.

[MSHappyCampers]

Hi ! Welcome to IRV2! We're sure glad you joined the gang!

I know I'm in the wrong owner's forum here, but I wanted to mention one thing that might help. I was having trouble with the "EE" code when resetting my 5-button thermostat. I had to turn off ALL florescent lights before it would reset!


I won't be following this thread but hope this might help!


Good luck, happy trails, and God bless!

[Farqs]

Thanks Joe.

I read your thread on that earlier. My unit did reset okay. Although I did not have any lights on at the time.

["007"]

Welcome to the forum.
The #1 jack second unit would be blank, if you swapped the AC's than you would need it in the front location as your first one is now used.
AC wiring diagrams in QT's #1 & # 2.
Another important link for you plus all links in my signature have answers for your Newmar.
Workhorse forum --- Important WH Info --- OEMY's web site --- Brochure --- Owners Guide
Enjoy the forum and safe travels.

[Farqs]

Thanks for the links and advice 007.