No power to Thermostat

Mikeeg · 11-02-2011, 04:20 PM

Went out to winterize and flipped on thermo for heat and no lights no numbers seem like no power.I checked all fuses and breakers all are good.Went on Duo-therms site for trouble shooting and checked fuses on both roof air units and they are good, looking for help!! I tried to test for 12 volt on phone cord at back of thermo can't seem to find any but not easy to test there with ohm meter.
This all worked about a month ago where did the power go is there another fuse I'am missing or maybe bad contacts up in the air conditioners. Does anyone no if there could be trouble in the furnace causing this I need help. Spent the day chasing 12volts and didn't find it.

This is on my 2001 Dutch star with a Duo-therm Comfort five button system, dual Penguin Air conditioners and Attwood heat.

harleyman134 · 11-02-2011, 05:01 PM

I had a similar problem earlier this year, turns out the control board on my a/c was bad. I found a guru who suggested it was a bad connection on the modular connection from the front control board to the tstat. From my weak memory, since I did not have a test cable he suggested I take the tstat off the wall and hook it up at the modular connection on the rear a/c making sure the tstat was "talking" to the control board on the front a/c. This was on a 5 button tstat.

**"007"** · 11-02-2011, 10:14 PM

Is your battery cut off switch operated maybe someone cut off the batteries.

Idaowl · 11-06-2011, 11:55 PM

Check your circuit breakers again. Flip them all the way off and back on. I don't know how they did it, but my AC breakers moved slightly to off. Enough to shut off power, not enough to visually indicate they had tripped.

Mikeeg · 11-07-2011, 08:00 AM

Check breakers multip. times check all dc fuses with test light looked at 3 amp fuse in rooftop air units but will take them out and test with amp. meter today. I down loaded CCC diagram and will go thru it all if I have no luck I have tech coming out to go thru it. Hoping it is and easy fix!!!!

**"007"** · 11-07-2011, 11:43 AM

Not sure which PDF you are using but this one is in Quick Tips.
Didn't know Newmar has been using the Atwood heaters thought they always used the Suburban heater.
Take a look at the thread about two troubles with the Atwood it may help you.
I believe your thermostat gets its 12V from the front AC control unit.
Do you have furnace indicated on display of 5 button control?
If not a dip switch has to be operated in the front AC control board.

Mikeeg · 11-07-2011, 02:18 PM

Didn't get to work on it today but that is the PDF I have with a better look and it is a Suburban heater, you are on the ball.

harleyman134 · 11-07-2011, 03:40 PM

Mike, sounds like you are looking in the right places, as you have figured out the tstat is powered by 12volts, generally you will have a 12volt line going to the control board on the front a/c from the coach, from the front control board 12volts is fed to the tstat and rear a/c control board. The front control board will have two sets of "phone cord" style wires coming off it, one of the lines will lead to the tstat and the other one will lead to the rear a/c. These phone line chords are connected just off the control board with a "modular" style connection. Since these modular connections are subject to condensation from the a/c it's possible that water has been introduced into these connections and the connections have failed. If you are getting 12 volts to the front a/c control board and if the fuse on the control board is good and you still don't have 12 volts to the tstat there's a good chance the failuree is at the modular connection. In the PDF files 007 you will see instructions for making a "patch" cord to check out the connections, just note you can't use a standard phone line as a patch cord.

Darrel · 11-08-2011, 01:02 PM

When I had your problem I reset the dip switches on the front AC and the furnace began working again. Of course I had also unplugged/replugged the phone cord connectors also.

Good Luck - Darrel

RobRV · 11-08-2011, 08:41 PM

We had the same problem about a Year ago. It took Me a while to trace the problem to a badly corroded Female Modular Socket on the front AC Board. I replaced the Socket and the Whole shebang is back to normal.

The Socket (Telephone Type) is available from several sources for about $1.00 or less!

You do need to unsolder the Old and carefully solder on the New!

Mikeeg · 12-15-2011, 05:34 PM

OK here is what I have. I had a tech route a new wire as there was no 12 volt going thru but had 12 volt before the phone style line to tstat at front a/c,who knows where the break is but now I have a new tstat wire with a few hrs.of rerouting. Now the heat is working fine but a/c loses the LCD readings except for zone (1-2) information until the unit reach there temp. and turns off then LCD information returns.The tech is contacting Newmar and Duo-Therm to see what the problem may be, my though is it may have to be reset what do you all think?

Somethings are hard to put in words!!!