Hi I have a 2006 Audi A6 3.0 TDI Avant Quattro that has a few issues that I am working through , the main one that I am struggling with is the temperature guage goes to half way (normal temperature) when car ignition is switched on . It doesn't matter whether car is hot or cold always same . I have changed what I thought was the temperature sensor that controls this to no avail . This sensor was at the back corner of the engine , accessible once air box pipe was removed . I have since been told that there is another temp sensor elsewhere . I am told that this may be underneath somewhere near the hoses that go in to the radiator . Has anyone on here any more ideas on this as I am running out of ideas . Thanks Ian