Question 1

Red LED slowly flashing (Undervoltage or overload)

Accepted Answer

Possible cause: Battery undervoltage, battery overload, or a defective battery. Check the battery, switch the charger off and on again, or replace the battery if defective.

Question 2

Red LED quickly flashing (Overheating)

Accepted Answer

Possible cause: Excessive ambient temperature (>40°C) or poor ventilation. Improve ventilation around the unit, maintain a minimum 25 cm clearance space, and reduce ambient temperature.

Question 3

Red LED permanently lit (Short circuit or reversed polarity)

Accepted Answer

Possible cause: Short circuit on output lines, reversed polarity, or a blown internal fuse. Connect the charger with correct polarity, rectify the short circuit, and check/replace the fuse if triggered.

Question 4

Red LED one quick flash, one slow flash (Fan fault)

Accepted Answer

Possible cause: Cooling fan failure or obstruction. Inspect the fan for dirt, physical obstruction, or damage, and replace if necessary.

Question 5

Red LED slow double flash (Starting battery connection fault)

Accepted Answer

Possible cause: Wiring fault or incorrect connection at the ESB starting battery terminal. Verify polarity and secure connection of the starting battery at the ESB socket.

Dometic MCA, MCA PLUS

Technical Specifications

Master Troubleshooting & Diagnostics Matrix

Error Code / Indicator	Symptom / Meaning	Possible Cause	Step-by-Step DIY Fix	Suggested Actions
`N/A`	Red LED slowly flashing (Undervoltage or overload)	Battery undervoltage, battery overload, or a defective battery	Check the battery, switch the charger off and on again, or replace the battery if defective.	DIY Safe
`N/A`	Red LED quickly flashing (Overheating)	Excessive ambient temperature (>40°C) or poor ventilation	Improve ventilation around the unit, maintain a minimum 25 cm clearance space, and reduce ambient temperature.	DIY Safe
`N/A`	Red LED permanently lit (Short circuit or reversed polarity)	Short circuit on output lines, reversed polarity, or a blown internal fuse	Connect the charger with correct polarity, rectify the short circuit, and check/replace the fuse if triggered.	DIY Safe
`N/A`	Red LED one quick flash, one slow flash (Fan fault)	Cooling fan failure or obstruction	Inspect the fan for dirt, physical obstruction, or damage, and replace if necessary.	DIY Safe
`N/A`	Red LED slow double flash (Starting battery connection fault)	Wiring fault or incorrect connection at the ESB starting battery terminal	Verify polarity and secure connection of the starting battery at the ESB socket.	DIY Safe