More Truma Trauma

I am not sure of the model number of the display unit but it has an Enet label, a centre rotary knob with a pushbutton in the centre
I have had the van hooked up with heater set low just to keep the chill off for two weeks.

I have just gone to prep van for a trip and the display is off. On turning it back on with the centre button the display shows only a miniature clock face and a spanner at the display bottom. A twiddle of the knob takes me through basic preferences and time setting and then returns to the same screen as when I turned it on 
, mini clock and spanner.
I have tried switching off and on again but it is the same.
Anyone have any suggestions?

Can try to reset, switch Truma and Sargent off, pull knob off and unscrew the screw you can the see. This lets you wiggle the Truma panel free, there should be two cables going into the back of the unit, unplug the larger plug, wait a few minutes then reconnect plug, put unit back and replace knob. Power on Sargent and Truma should hopefully reset it for you

Don't know why we bother. Suggestions asked for, suggestion (that has worked for me in the past) offered, no feedback if was tried or if it worked or not. Will go back into hibernation and mind my own business.

Bilbobaggins wrote:Can try to reset, switch Truma and Sargent off, pull knob off and unscrew the screw you can the see. This lets you wiggle the Truma panel free, there should be two cables going into the back of the unit, unplug the larger plug, wait a few minutes then reconnect plug, put unit back and replace knob. Power on Sargent and Truma should hopefully reset it for you

I take the point of your next post but its much easier to reset on that van by shutting down the EC500 power supply and after 5 min, powering up again.

These sort of 'faults' are usually the result of the operator not following the correct sequence of operations.

I found when I had clock and spanner a few times switch off ec500 at main switch on unit and switch of Truma by pressing and holding button till the OFF message comes up leave for 15 minutes and switch ec500 on first then Truma it will be ok. I have to agree with Billoboagins it is not hard to give update. Kevin

Bilbobaggins wrote:Don't know why we bother. Suggestions asked for, suggestion (that has worked for me in the past) offered, no feedback if was tried or if it worked or not. Will go back into hibernation and mind my own business.

The reason for no update  that is I only got to try it today.
I did try as you suggested but it didn't work.
So I did the following and it worked. Remove the cover on the heater exposing the connectors and the fuse. Unplug the voltage feed to the heater unit and then disconnect the data cable, wait a few seconds reconnect the data line and then the voltage cable.
Return to the control unit and select spanner, then scroll through to reset. This comes up with PRSet,push the button again and bingo. 
So a loss in comms between the head set and the main unit was the problem in my case.