Dometic Air Conditioner: “E7”
warning RV air conditioner error codes
What it means
The CCC2 has lost 120 VAC line power to all of the air conditioner power module boards, so the entire system shuts down. It signals an incoming-power problem, not a fault inside the thermostat itself.
Most likely causes
- Tripped pedestal/shore-power breaker or general loss of shore power most likely
- Blown 120 VAC fuse or breaker feeding the AC circuit common
- Faulty automatic transfer switch (works on generator but not shore power, or vice versa) less common
- Damaged power cord plug, burnt blades, or loose/corroded connection less common
Safe checks you can do yourself
- Check the shore-power pedestal breaker: switch it fully off, then back on.
- Verify the RV's own 120V breakers for the air conditioner have not tripped, and reset any that have.
- If you have two units, note whether one or both show E7 to localize the power loss.
- Inspect the power cord plug and pedestal outlet for burning, corrosion, or bent/broken prongs (with power off).
- If the AC runs on generator power but not on shore power, suspect the transfer switch.
How to reset / clear E7
- Restore 120 VAC power to the unit.
- Disconnect all power for at least 5 minutes, or press and hold MODE and ZONE together, release, then press ON/OFF to reset the thermostat.
- Power the system back up and confirm E7 has cleared.
When to call a technician
Call a technician (or electrician for the pedestal) if breakers and fuses are fine but 120V is still not reaching the unit, or if you suspect a failed transfer switch.
Applies to
Dometic Brisk II · Dometic Penguin II · CCC2-controlled rooftop units
FAQ
What does Dometic Air Conditioner code "E7" mean?
The CCC2 has lost 120 VAC line power to all of the air conditioner power module boards, so the entire system shuts down. It signals an incoming-power problem, not a fault inside the thermostat itself.
How do I reset Dometic Air Conditioner E7?
Restore 120 VAC power to the unit. Disconnect all power for at least 5 minutes, or press and hold MODE and ZONE together, release, then press ON/OFF to reset the thermostat. Power the system back up and confirm E7 has cleared.
What is the most common cause of E7 on a Dometic Air Conditioner?
The most likely cause is tripped pedestal/shore-power breaker or general loss of shore power.
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Sources
- Comfort Control Center 2 Thermostat User's Guide — Form No. 3314150.016, LCD Error Code section, E7 (Dometic LLC (hosted by My RV Works))
- Getting An E7 Code on Your Dometic Thermostat? What It Means & How to Fix It! — E7 meaning and troubleshooting steps (The RV Geeks)
Note: E7 points to incoming 120V power loss; if power is confirmed present at the unit, the fault may lie in wiring between the breaker and the power module.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.