Thermostat displays E13 and may disable dehumidification or show erratic humidity control.

Safety first: Turn off power to the HVAC system and dehumidifier at the breaker.

• Step 1 – Verify configuration: In the thermostat's advanced settings, confirm that a dehumidifier is enabled only if one is installed.
• Step 2 – Inspect DHUM wiring: At the thermostat, check that the DHUM wire is secure and not touching other terminals. At the dehumidifier or Carrier control board, verify correct landing per the installation manual.
• Step 3 – Isolate dehumidifier: Temporarily disconnect the DHUM wire at the thermostat, restore power, and see if E13 clears. If it does, the issue is in the dehumidifier or its wiring.
• Step 4 – Check dehumidifier operation: Manually start the dehumidifier (if it has local controls) to verify it runs. If it does not, the internal control board may be failed.
• Step 5 – Replace faulty component: Replace damaged wiring or the Carrier dehumidifier control board as needed.
• When to call a pro: Dehumidifier airflow and condensate management should be verified by a technician after repairs.