Zone 2 not happening with 2002 HR Endeavor - Duo Therm 5 button system

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New member
Jul 11, 2013
Hello - first time on this forum. Thanks in advance. Our 2002 HR Endeavor coach has a two-zone heat and cooling system. Zone 2 is not coming up on the thermostat. We have tried the factory reset - checked the 3amp fuse on the rear unit - and tried switching around the cat5 cables to get it going. No rear cooling and rear furnace also not coming on line. There is 110 power to the rear unit per my voltmeter.

The rear roof unit is a duo Therm product #991721743 with electrical kit 3109226.005 installed.

We love the coach - new to us last December - but sure would like the AC unit especially to work.

Dip switch problem??? New circuit board needed??? Any hints from the net?

Mike D.
Check the dip switches in the A/C units.  They're accessible from inside the RV when you remove the filter and bezel.  They tell the thermostat what your configuration is and which is zone 1 and zone 2.  You may need the manual for the Dometic Comfort Control but the switches are labeled as I recall.
When I bought a new Bounder some time back it soon had the same symptoms. After multiple trips to the dealer, and several parts replaced (warranty, thankfully), it turned out to be a bad control board in the front airconditioner (zone 1). Of course you should try the cheaper/easier things first.
Since you said you have A/C to unit evidenced by your voltmeter, I would check for DC power to the board from thermostat. roughly 4.76vdc should be present I believe. I would like more info, do you hear board "click" at all?
I had the same problem.  Thinking, OK I can fix this, I jumped in.  I changed the thermostat, control board on the front A/C, (zone 1), changed the control wiring , which required me to buy the special tool to put RJ-11 end connectors on new wiring, and I even ran new wiring from the front A/C thru the ductwork to the thermostat located in the middle of the coach.  I did learn that the control wiring goes from the thermostat to the left RJ-11 connector on the front A/C control board.  The control cable then goes from the right bottom connector on the front A/C control board to the back A/C control board.  Also the dip switches on the front A/C are all off, (left position) and the dip switches on the back A/C have the second dip switch turned on.  I also found out that only the front A/C has a 12 volt DC feed.  The back A/C gets its 12 volt control voltage from the control cable that comes from the front A/C board. 

After doing all this I still did not have a working system.  I bit the bullet and called around for pricing to replace everything.  I have Duo Therm penguin A/Cs with heat pumps. They are both model 630515.321.  The best price I found was $975 each plus tax and installation was 4 hours at $120.
I also discovered that the newer replacement model requires a digital programable thermostat instead of the 5 button comfort control thermostat of the old system.  I had to buy a new thermostat for about $130.  Bottom line is about $2,800 later I have replaced the entire system and it works great.  Sorry for the rambling post but I thought someone might use the information.

After telling you all this I would place money on your problem being the front control board that send 12 volts to the rear A/C unit and control signals from the thermostat.

I would gladly give you the new control board I just replaced, However I had the dealer put the old A/C units in the boxes from the new units and gave them to two campers here that needed A/C units.  They were both still functional when operated alone as single units wired directly to thermostats.
Thanks for the responses and tips. I will looking and checking out the leads offered and report back later.
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