Factory fitted diesel night heater MP2017

My on board factory fitted night diesel heater seems to have stopped working. The heater fires up then blows cold air then shuts down and the on board display shows the heater symbol with one single line through it but no number. Looking for a solution. Full tank etc

It behaves like this when your camping battery has low voltage. Have you tried with the engine running?

I’ll give it a go and feedback

It works with the engine running you are right. Does this mean the leisure battery needs to be replaced?