Hello,
I have a problem with my 9N in that last week the temperature warning light popped up on the dash and now I don't seem to be able to get rid of. I'll try and summarise here:
- temp warning light came on - it was a hot day but temp gauge read 90 (as it should) and the coolant level was fine
- pulled over and engine cooled to 70
- started up again and all ok. then warning light came back on after 1/2 mile. Coolant temp and level still fine but I waited a little longer
- started again, light came on again, but I just drove home anyway because I didn't believe what it was telling me. Got home fine and the temp gauge didn't get above 90
Since then the light has come on randomly. Sometimes not at all. Sometimes 10 seconds after starting. Sometimes without starting.
So, my thoughts were that it's either a problem with the temp switch in the stat or the coolant level sensor. Or maybe the ECU (I'll get to that)? I unplugged the level sensor, cleaned the contacts, and reconnected after getting a good resistance reading (not open circuit). Started the car and it was fine. Shut the drivers door and stood watched the engine for a few minutes. Went and checked dash, still no light. Job done. Then I opened the drivers door and the temp warning light came back on with the interior light. And strangely since then driver elec window is manual only (if i press the button all the way it doesn't open on its own - I have to hold it down).
This door business is making me think it's maybe an ECU fault. I'm happy that the car isn't overheating and that the coolant level is ok. There's no leak. There's no oil in the water. The temp gauge has never gotten above 90. Could it be that maybe it did overheat and the ECU is confused now - it thinks it's overheating but it's not? I have a new coolant temp switch to try, but I'm not convinced that it the problem. I think it's electrical but I don't know where to start with checking. Was tempted to get a VAG COM cable but I have a mac and don't really want to install a partition for windows just for diagnostics.
Sorry, that's an essay, but it's not a straight forward problem. I'd be very grateful if anyone else has experience of this sort of problem and has anything they could share. Is there anything else I could try myself before I concede and take it to a garage? Thank you kindly.