No display on Dometic thermostat?

[kdubinwa]

Any quick fixes? Fuse checked. Batter switch on. Have plenty of volts. Saw this work fine at the Pdi and no dragging it back and would like some heat for the night!
Kurt

 

[danemayer]

Re: No domestic thermostat.display?

1. Did you check the fuses with a meter?
2. Are other 12V devices working? Like inside lights.
3. Is thermostat mode set to HEAT?
4. Which thermostat is it?

 

[jbeletti]

Kurt,

I've had to power cycle mine recently. As there's no power switch on it, I pulled the 12 volt fuse in the fuse panel for it.

If the fuse is good and you measured 12 VDC at the back of the thermostat, I'd guess you have a thermostat issue.

Do you have a second thermostat in the coach you can swap in to troubleshoot?

 

[Jesstruckn/Jesstalkn]

Like Jim mentioned if you have 2 units check the other one first if it works then swap them and see what you get.

 

[kdubinwa]

Have. 12 volt at fuse. Fuse good. I'll check second thermostat. Lcd does not display anything on the main T sat

It worked during pdi but we were also connected to shore power. Maybe it didn't get wired up correctly for dc or I have a loose wire. Back of t stat uses a phone cable terminator

 

[bobw]

You must be connected to AC power to work heat or ac.

 

[kdubinwa]

No way....

You must be connected to AC power to work heat or ac.

- - - Updated - - -

My responses are abbreviated as I'm driving the 5th wheel home from the dealer. 2100 miles The bedroom t-stat does have power. The main-stat does not. It appears the bedroom t-stat is programmed only for zone 1. I called for heat and fan for zone 1 and did not get any furnace response. Not hooked up to shore power in parking lot so could not test bedroom a/c. I'll have try swapping the T-stats tomorrow. Strange this did not occur during the PDI, but that is life.

- - - Updated - - -

 

[danemayer]

Check the wire connections on the thermostat. Maybe just a loose wire.

 

[kdubinwa]

The wire connection is a pre-crimped telephone jack terminator.

Check the wire connections on the thermostat. Maybe just a loose wire.

 

[danemayer]

The wire connection is a pre-crimped telephone jack terminator.

That wire goes up into the ceiling, to a control box usually located under the living room Air Conditioner. I believe that's where the thermostat's 5V DC comes from, and when the thermostat closes, it operates a 12V relay in that box that sends power to the furnace control board and blower.

If your two thermostats are the same, you can swap them to see if the problem is with the thermostat or elsewhere. If the other thermostat acts the same, see if you can find the control box. Be careful opening it as it may also have 120V AC inside. You'll need a step ladder and don't want to touch a live circuit while on a step ladder.

 

[kdubinwa]

I have the whisper system so its probably under the shroud on the roof ....as there are no interior ac panels. Will have to wait until it is in my driveway this Saturday before checking that. I need to get my profile updated now that I'm more than a lurker!

That wire goes up into the ceiling, to a control box usually located under the living room Air Conditioner. I believe that's where the thermostat's 5V DC comes from, and when the thermostat closes, it operates a 12V relay in that box that sends power to the furnace control board and blower.

If your two thermostats are the same, you can swap them to see if the problem is with the thermostat or elsewhere. If the other thermostat acts the same, see if you can find the control box. Be careful opening it as it may also have 120V AC inside. You'll need a step ladder and don't want to touch a live circuit while on a step ladder.