Only Getting A Lit LED Screen On The Advent ADV24QR Thermostat
Updated 10/27/2026 | Published 10/22/2026
Question:
I installed an ADV38SR 15K AC unit with the ADV24QR thermostat. I am getting a lit up LCD screen, but no information showing. I went through some troubleshooting and have confirmed i have 13.0V at the Thermostat. Any suggestions on what else to check/test to try to determine why this is not functioning?
asked by: Scott O
Expert Reply:
Welcome back, Scott! Wish it were under better circumstances though.
Since you're getting a blue backlit screen and have confirmed 13V at the # ADV24QR thermostat, we know it's receiving power. The issue is likely a communication problem between the thermostat and the ceiling control box. I'd recommend starting with a few quick checks:
1. Check the wiring: Make sure communication wires A and B are connected correctly at both ends, with no loose or crossed connections.
2. Reset the system: Remove the 12V fuse powering the thermostat for 2–3 minutes, then reinstall it to see if the display resets.
3. Inspect the connections: Check for any loose or damaged splices, especially on the communication wires.
4. Check the mounting screws: Make sure they aren't overtightened, which could put stress on the thermostat housing. (I know this one sounds weird, but we have seen it happen before)
If everything checks out and the screen is still blank, the issue may be with the thermostat or ceiling control box itself, and a replacement is likely needed.
Have you had a chance to check the wiring connections between the thermostat and the ceiling control box, or have you mainly been focusing on the power supply so far?
Product Page this Question was Asked From
Air Distribution Box with Wall-Mounted Thermostat for Advent Air RV Air Conditioners - Ducted - R32
- Accessories and Parts
- RV Air Conditioners
- Air Distribution Box
- White
- Advent Air
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Scott O.
10/23/2026
Thanks and I just tried taking the thermostat back to the control box and wired the 4 T-Stat bound wires as follows....Black - GND, RED-12V, Green - A and White -B. Still have no display on the T-Stat so not sure what else to try from here.