Dometic Air Conditioner: “E9”
warning RV air conditioner error codes
What it means
Invalid zone configuration: the dehumidifier DIP switch and either the heat pump or heat strip DIP switch are both set ON in the same zone, an unsupported combination. The CCC2 locks out heat pump, heat strip, air conditioning, and dehumidify in that zone.
Most likely causes
- Dehumidifier DIP switch ON together with the heat pump or heat strip DIP switch in one zone most likely
- Incorrect DIP-switch settings after a board replacement or reconfiguration common
Safe checks you can do yourself
- Treat E9 as a configuration error, not a component failure; it usually follows recent install or service work.
- Identify the blinking zone so the correct power module can be checked.
How to reset / clear E9
- Correcting the conflicting DIP-switch settings requires access to the affected zone's power module, normally a service step.
- After a valid DIP-switch combination is set, cycle power off and on to clear the code.
When to call a technician
Call an RV technician to correct the DIP-switch configuration, since the change is made inside the line-voltage power module.
Applies to
Dometic Brisk II · Dometic Penguin II · CCC2 zones with dehumidifier plus heat pump or heat strip options
FAQ
What does Dometic Air Conditioner code "E9" mean?
Invalid zone configuration: the dehumidifier DIP switch and either the heat pump or heat strip DIP switch are both set ON in the same zone, an unsupported combination. The CCC2 locks out heat pump, heat strip, air conditioning, and dehumidify in that zone.
How do I reset Dometic Air Conditioner E9?
Correcting the conflicting DIP-switch settings requires access to the affected zone's power module, normally a service step. After a valid DIP-switch combination is set, cycle power off and on to clear the code.
What is the most common cause of E9 on a Dometic Air Conditioner?
The most likely cause is dehumidifier dip switch on together with the heat pump or heat strip dip switch in one zone.
Related · Dometic air conditioner
Electronics and drive faults on the FreshJet inverter board.… E1
The thermostat has lost its communication link with the air … E2
The indoor (return-air) temperature sensor is reading open-c… E3
The indoor (return-air) temperature sensor is reading as sho… E4
The outdoor temperature sensor (fitted on select heat-pump m… E5
The freeze sensor is reading open-circuit or out of range (d…
Sources
- Comfort Control Center 2 Thermostat User's Guide — Form No. 3314150.016, LCD Error Code section, E9 (Dometic LLC (hosted by My RV Works))
- Dometic Comfort Control Center 2 Users Guide — Error code table, E9 (thermostat.guide)
Note: E9 is a setup/configuration fault that normally appears after installation or service, not during routine operation.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.