My 2007 CRDi trajet seems to occasionally show a false reading on the temperature gauge when the interior fan or headlights are on. The aircon doesn't even have to be on. The engine isn't that hot when the gauge reports high, I have had Hyundai service centre look at this as well as another workshop. They cannot find the issue. Another strange symptom is that when the gauge is showing high and I turn off the ignition and then on again the temperature gauge goes back to its usual position between 1/4 and 1/2 then after 10 mins it climbs again. Any suggestions would be appreciated.