MattS
Active member
Does anyone know enough about older Eberspacher heaters to tell me exactly what the connections are on my controller, and what I should expect to see across which terminals with a multimeter?
I think it’s a 301 series controller.
I’m trying to diagnose whether my thermostat on the controller is duff…
I’ve spent hours now reading through old forum posts, the content on LeTonkinois site, and various Eberspacher manuals. I’ve even had a big hand from ChatGPT!
I just can’t find anything that matches my connections and controller exactly, or explains clearly how each terminal controls the operation. The wire colours don’t seem to align with the standard colours in the manuals, and I can’t work out what every terminal does.
Any pointers or answers much appreciated!


I think it’s a 301 series controller.
I’m trying to diagnose whether my thermostat on the controller is duff…
I’ve spent hours now reading through old forum posts, the content on LeTonkinois site, and various Eberspacher manuals. I’ve even had a big hand from ChatGPT!
I just can’t find anything that matches my connections and controller exactly, or explains clearly how each terminal controls the operation. The wire colours don’t seem to align with the standard colours in the manuals, and I can’t work out what every terminal does.
Any pointers or answers much appreciated!

