Thermostat not working

GANGGREEN · 05-23-2021, 10:23 AM

Came back to the campground to de-winterize my 38 bhds Jay flight and found that the thermostat isn't working at all, I can't even turn it on. Is there something simple that I'm missing or is the unit just shot and needs replaced?

Grumpy · 05-23-2021, 10:35 AM

Got to ask. Did you check the fuses..also the one for the furnace and there may be one in the thermostat? Is there a reset on your furnace sometimes they are connected together. Also pull the thermostat and pull the wires out of the wall some times there is an in-line fuse there too.(I know dumb, but it could be there).

GANGGREEN · 05-23-2021, 10:52 AM

I checked the fuses and breakers and don't see a problem. I'll try pulling the thermostat and looking for an inline fuse.

GANGGREEN · 05-23-2021, 10:56 AM

Nope, I don't see an inline fuse behind the thermostat nor do I see any chewed wires or anything. I don't have a circuit tester with me.

craigav · 05-23-2021, 11:04 AM

Perhaps it is not the thermostat and instead it is the heater or A/C that isn't getting power. Have you tried both heat and A/C to see if either turns on with the thermostat? If so then the issue is likely not the thermostat. ~CA

GANGGREEN · 05-23-2021, 11:12 AM

I can't toggle from heat to cool at all because nothing comes up on the thermostat.

JimD · 05-23-2021, 01:18 PM

Without checking for voltage at the thermostat you will just be spinning your wheels.

GANGGREEN · 05-23-2021, 04:34 PM

That will be next then, thanks all.

Marcm157 · 05-23-2021, 04:43 PM

Quote:

Originally Posted by JimD

Without checking for voltage at the thermostat you will just be spinning your wheels.

I agree plus if you DO have voltage at the Tstat, you can jump the 12 volts to the other terminals and see if the devices they are controlling start up. Then you can pretty much say the thermostat is shot...

dave89 · 05-24-2021, 05:14 PM

Is there by any chance batteries in the t-stat? Ours takes 2 AAA batteries. Not sure what make and model you have. Both the one I have in the house and the camper have batteries to power them up.

**norty1** · 05-24-2021, 05:22 PM

The Mach III thermostats operate on 12vdc. No internal batteries.

GANGGREEN · 05-24-2021, 06:27 PM

Quote:

Originally Posted by dave89

Is there by any chance batteries in the t-stat? Ours takes 2 AAA batteries. Not sure what make and model you have. Both the one I have in the house and the camper have batteries to power them up.

No, no batteries in mine.

dave89 · 05-29-2021, 07:36 AM

Well, it was a thought seeing that there are so many different T-stats out there. It looks as if, as the others have said, it's time to get the voltmeter out. Good luck.

**norty1** · 05-29-2021, 08:30 AM

Be cautious when testing voltages on the thermostat. Shorting the wrong wires with it connected can destroy it.

dave89 · 05-29-2021, 11:18 AM

I took a bit of time to do some looking up on the t-stat your having problems with. I found a couple of pictures that show a fuse on the front circuit board in the t-stat. I know that you haven't been able to locate one. Did you check there? It's a 2 amp short fuse.

firechf040 · 06-09-2021, 12:15 PM

I had this happen when my inverter went out. Check to make sure you have 12 to 14 volts at your battery.

RWOODY · 06-09-2021, 04:51 PM

The power to the Stat comes from the furnace. Try the reset on the side of the furnace. That's how my Jayco is wired. Crazy but true.

chas111 · 10-19-2023, 09:39 PM

Quote:

Originally Posted by RWOODY

The power to the Stat comes from the furnace. Try the reset on the side of the furnace. That's how my Jayco is wired. Crazy but true.

Thanks for the tip. I found the power wire was rubbing against the furnace and it shorted out! A little tape and fuse - ready to go.

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