What Does It Mean If My Furrion Thermostat Is Flashing LO

Updated 10/28/2025 | Published 03/04/2023

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Digital Multimeter with 42" Long Test Leads - LED Display

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Question:

What does Lo code on thermostat mean? Ac and dc power are on to controller. Nothing works. Just a Lo code on thermostat.

asked by: Robert

Expert Reply:

According to the owner's manual if your Replacement Premium Wall Thermostat for Furrion Chill HE RV Air Conditioner # FR33PR is flashing LO then that means you have an insufficient low-level 12V power supply.

I recommend checking your wiring and connections to the thermostat and ensure that you are in fact getting an adequate 12V with a multimeter # PT89ZR.

If you verify that you are getting 12Vand all of your wiring is good, come back and we can continue to troubleshoot deeper.

expert reply by: Bryce D

Mike S.

4/15/2025

I have 13.5 to my thermastat and it is still flashing lo. What could it be

Bryce D.

4/16/2025

@MikeS Hey Mike, since you're getting the correct voltage and you're still getting the error, then it sounds like there is actually something wrong with the thermostat itself, likely the temperature sensor. Your next move here should be to replace the thermostat with the Replacement Premium Wall Thermostat for Furrion Chill HE RV Air Conditioner # FR33PR. Let me know if there is anything else I can do for you, and I'd be happy to help!

Doug

7/16/2025

@BryceD I'm having the same issue. I have replaced both batteries and the thermostat. The first time I turned the new thermostat on it worked but then it went right back to flashing LO after that. The voltage at the thermostat reads 13.2V. Any help would be greatly appreciated.

Doug

7/16/2025

@BryceD also it works with shore power just not battery power. The model of the thermostat is FACW10ESSA-BL