I had the sensor bulb come loose from the plastic slider. I used a little silicone to hold it in place. On mine, the bulb is supposed to be even with the top of the slider. I also use a spring type paper clip to help hold it in place so it does not move while traveling. If this is not your issue, there is a kit, I think it is called the "snip the tip",
Dometic Thermistor Repair Kit