Dometic Portable Cooler: “Warning 33 (compressor start)”
warning Dometic cooler error codes
What it means
The cooler's controller tried to start the compressor but it did not start, so the controller flags a start failure. This is frequently triggered by marginal supply voltage rather than a dead compressor.
Most likely causes
- Supply voltage too low/sagging when the compressor tries to start most likely
- Internal controller or compressor relay fault common
- Loose or corroded power connection causing voltage drop on start less common
Safe checks you can do yourself
- Confirm a strong supply voltage under load (charge the battery or run on AC).
- Check the DC plug and socket for a tight, clean, corrosion-free connection.
- Give the cooler room to start — ensure it is upright and not in extreme heat.
How to reset / clear Warning 33 (compressor start)
- Switch the cooler off and disconnect power.
- Wait at least 5 minutes.
- Reconnect power and switch it back on.
- If the warning returns, contact Dometic customer service.
When to call a technician
The warning persists after a full 5-minute power-off restart with confirmed good voltage — that indicates an internal compressor or controller fault requiring service.
Applies to
CFX3 25 · CFX3 35 · CFX3 45 · CFX3 55 · CFX3 55IM · CFX3 75DZ · CFX3 95DZ · CFX3 100
FAQ
What does Dometic Portable Cooler code "Warning 33 (compressor start)" mean?
The cooler's controller tried to start the compressor but it did not start, so the controller flags a start failure. This is frequently triggered by marginal supply voltage rather than a dead compressor.
How do I reset Dometic Portable Cooler Warning 33 (compressor start)?
Switch the cooler off and disconnect power. Wait at least 5 minutes. Reconnect power and switch it back on. If the warning returns, contact Dometic customer service.
What is the most common cause of Warning 33 (compressor start) on a Dometic Portable Cooler?
The most likely cause is supply voltage too low/sagging when the compressor tries to start.
Related · Dometic portable cooler
The cooler stopped running on 12/24V DC because the incoming… Warning 01 / 02 (NTC sensor)
The cooler's temperature sensor (an NTC thermistor) reads as… Warning 03 / 43 (communication)
An internal communication fault between the cooler's electro… Warning 11 / 12 (NTC sensor)
Same kind of temperature-sensor fault as Warning 01/02, but … Warning 32 (fan overcurrent)
The cooling fan is drawing more current than allowed, which … Warning 34 (compressor speed)
The compressor is running but cannot reach or hold its targe…
Sources
- !WARNING 33 Compressor start fail | CFX3 Coolers | Support — CFX3 alert & warning codes — Warning 33 (Dometic)
- I see an alert message or warning code | CFX3 Coolers | Support — CFX3 warning code index (Dometic)
Note: Dometic's page gives the meaning (internal fault) and the off-5-minutes-then-restart remedy; the strong real-world link to low supply voltage is from multiple owner reports, so treat voltage as the first thing to check before assuming hardware failure.
● Last verified 2026-06-29 · compiled from manufacturer documentation. Codes can vary by model year — always cross-check your unit’s manual.