Dometic Air Conditioner: “E5”
warning RV air conditioner error codes
What it means
The freeze sensor is reading open-circuit or out of range (documented on the Single Zone LCD thermostat). Air conditioner (cooling) mode is locked out, while furnace, heat strip, heat pump, and fan can still run, with the display showing the last temperature set-point.
Most likely causes
- Disconnected, broken, or out-of-range freeze (coil) sensor most likely
- Loose or corroded freeze-sensor wiring/connector common
- Failed control board sensor input less common
Safe checks you can do yourself
- Power-cycle the system at the breaker to confirm the fault is persistent.
- Confirm that furnace/heat and fan still operate while cooling is locked out, which matches a freeze-sensor fault.
- If accessible, check the freeze-sensor connector seating; do not perform internal repairs yourself.
How to reset / clear E5
- Turn the thermostat OFF.
- Remove power at the AC breaker for about a minute, then restore power.
- If E5 returns, the freeze sensor or its wiring requires service.
When to call a technician
If E5 persists and cooling stays locked out, have a technician test/replace the freeze sensor and verify the control board.
Applies to
Dometic Single Zone LCD thermostat systems (freeze sensor)
FAQ
What does Dometic Air Conditioner code "E5" mean?
The freeze sensor is reading open-circuit or out of range (documented on the Single Zone LCD thermostat). Air conditioner (cooling) mode is locked out, while furnace, heat strip, heat pump, and fan can still run, with the display showing the last temperature set-point.
How do I reset Dometic Air Conditioner E5?
Turn the thermostat OFF. Remove power at the AC breaker for about a minute, then restore power. If E5 returns, the freeze sensor or its wiring requires service.
What is the most common cause of E5 on a Dometic Air Conditioner?
The most likely cause is disconnected, broken, or out-of-range freeze (coil) sensor.
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Sources
- Single Zone LCD Thermostat User's Guide — LCD Error Code (Error Code: E5) (Dometic (via Prime Time RV component manuals))
Note: E5 (freeze sensor) is documented in the Single Zone LCD thermostat guide; it was not listed in the CCC2 guide reviewed, so on CCC2 systems the freeze-sensor handling may differ. Verified from one official Dometic guide only.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.