That looks like a loose wire on the sensor somewhere. See pic, there is one of these for the front and one for the back, look under the upper cabinets toward the middle or rear.
Should have two wires behind it. If you have an ohmmeter and can get to the contacts on the back, the circuit should measure about 10K ohm give or take with temp.
The two wires run through the unit (always the long way and always in a conduit) back to your control box. In the back of the control box you should see labels on the lid, this should tell you which wires to look for.
I had one just after I picked up it up new where the temp sensor was a bit intermittent, found a pitched wire in the cabinet right behind the sensor where the wire was. As soon as I pulled it out it looked like somebody bent it bad and then installed it anyhow. Soldered a bit, works great.
Worked until it cleared the curbs on the dealer's lot.