Our Hymer B544 PL, is built on a Fiat Ducato chassis, recently the external temperature shown on the instrument panel has been erratic, showing very high temperatures that were clearly not correct.

Temperature showing —°C

Finally the display changed to —°C, just three dashes. This suggests to me that the external temperature sensor has failed. Not only that, but there appeared to be a problem with the cab heater too, the heater control had to be turned up very high to get any heat from the heater. That suggests that the two temperatures are linked in some way.

Preliminary research indicates that the temperature sensor has failed, the bigger problem now is finding the sensor so that it can be replaced. On standard Fiat Ducato vans the external temperature sensor is located in the driver’s side mirror, but because the Hymer is built on the Fiat Ducato chassis, there is no standard mirror, so where is the external temperature sensor?

This is going to be an interesting project, I sense a lot of frustration in the days to come.

Keywords: Fiat Ducato external temperature sensor problem