We have a 5 year old waeco that will no longer work on 12 volt. It works very well on 240 but shows a red error light as soon as we switch it over. All the leads are good and 12 volt plug.
I have an old Engel and it won't work on 12 volt either the cost to repair was way too much. So what i did was i bought a 300 watt inverter and run it in the back of my car. Hope this helps if yours woRks out cost prohibitive to repair