The Temp Sensor controls the heating temperature on your Diesel Heater and monitors the flame combustion process. If any unusual temperature change gets detected, the overheat sensor will send a digital signal and transmit it to the chip.
 
When this sensor fails your diesel heater will get locked into Shut down mode with the fan continuously blowing, this is the main failure that happens to these diesel heaters and is a simply 5 min repair with this replacement plug in part.
 
A must have spare part for your van