That sounds like the one on my old carioca 15P thought 1-9 was blower speed + amount of heatMy Truma has a switch with 5 positions
1 o clock = Hotwater and Heating High
2 H& H low
3 Off
4 Hot water low
5 hot water high
there is a dial which goes from 1 to 9 wich contos the level of heating with a grren light
theres is a simple thermastat near the switch..No obviously a thermostat. (more like a black "dead screwhead")
But it does cut the heating off when the vehicle is up to temperature
Never had a problem with heating so didn't know what thermostat looked like - if it is the size of a 1p never looked at it and i assumed it was a warning buzzer - but i do need glasses for close up and without them i couldn't read the truma word across the front