Hi all i would like to start by saying hello as this is my first post here. i have a 2003 a4 1.9tdi sport and have an issue with the car temperature. the gauge was reading 88'ish and the temp would go down if i put the heater on. auto mode or not got the same result. i still have heat in the cab. off the back of this i had the thermastat changed and seal. now the car hits 90 on the dot. problem i have is that when i run the heater it still drops ( as low as 45 ). turn the heater off and the temp will slowly go back to 90. as far as now, it has never gone over 90 :0) can anyone suggest what is causing this problem. if i dont use the heating its not an issue but i hate gremlins and need to solve this. all your help and advice is most appreciated. i will vag test it once i get the correct version of sotware for my after market cable as i have lost the disc and cant remember which revision i had with it.