High pitched tone, coming from furnace area

[wfrauch]

Greetings - first thanks to all, have been lurking here for a couple weeks trying to learn as much as I can before we pulled the trigger on our new-to-us 2019 Thor Vegas 27.7.

To make a long story short-ish.
The high pitched sound is coming from the furnace area.
This starts when I simply turn the igition key on, or to "ACC".
The furnace is not running. No fans going.
I have pulled each of the fuses out, one at a time, no effect.
I have turned House power off (the one in the entrance step well), no effect.
I switched the breaker off at the fuse panel, no effect.
Turning the furnace on, it functions normally, no effect on sound.
Turning the ignition off, and sound stops.
No gas smell, no alarms displaying anywhere.

Found some schematics on the Thor website, but the furnace unit doesnt really show whats inside, for any solenoid/sensor/whatever.

Im at a total loss now, really really don't want to try to remove the entire
furnace.

ANY ideas would be much appreciated.

Thanks

I

[Chateau_Nomad]

We have a 2020 Thor Chateau 24F. Last summer I did a "stupid"... We set up late in the evening at a campground, and didn't get perfectly level, but good enough for the first night. So the next morning I decide to level up a little better. I started the engine and shifted into drive to inch forward. I noticed a "not so loud" high pitched tone I had never heard before. Well, I went ahead and inched forward... and heard my wife yelling from behind the coach "STOP STOP STOP!"
Long story even longer... The "very quiet high pitched noise" was a feeble alarm that the stabilizer jacks were down. So I spent the next half hour hammering and prying the jacks enough to get them retracted. Fortunately they weren't destroyed... and with a little TLC when we got home, they're fine.
Maybe cycle your stab jacks a few times... see if they are fully retracted? Other than that, possibly CO2 detector?

[wfrauch]

Thanks, Chateau -
Def not the CO/LP detector.
I will exercise the stabilizers to see if that has any effect.
If it does turn out to be that, it is a totally weird place to put an alarm emitter!!
Do you recall where the emitter was located?

Cheers

[wfrauch]

Originally Posted by Chateau_Nomad

We have a 2020 Thor Chateau 24F. Last summer I did a "stupid"... We set up late in the evening at a campground, and didn't get perfectly level, but good enough for the first night. So the next morning I decide to level up a little better. I started the engine and shifted into drive to inch forward. I noticed a "not so loud" high pitched tone I had never heard before. Well, I went ahead and inched forward... and heard my wife yelling from behind the coach "STOP STOP STOP!"
Long story even longer... The "very quiet high pitched noise" was a feeble alarm that the stabilizer jacks were down. So I spent the next half hour hammering and prying the jacks enough to get them retracted. Fortunately they weren't destroyed... and with a little TLC when we got home, they're fine.
Maybe cycle your stab jacks a few times... see if they are fully retracted? Other than that, possibly CO2 detector?

Found the culprit! Your issue gave me clues, after being on a wild goose chase. At one point, I had turned off the LP tank main valve, and the tone/alarm stopped. Imagine my confusion.

The real culprit was the plunger-type sensor at the end of the screw-jack.
As the screw turned in to its fully retracted resting place, the sensor was not detecting it was now pushed in. Two squirts of WD-40, and now it works, plus a little of adjustment of about 1/8 inch on its position.

Thanks!