Thread: D2 Td5 electric fan always on

Thanks again for all the ideas and suggestions.

The only update is that I have gone through all HawkEye menus and have been unable to find an error code obviously connected with the electric fan running continuously while the engine is on. (The HawkEye I have is a dedicated D2 Td5, but may not be as useful as a Nanocom - not sure?). I did the HVAC tests suggested by Tins (which I now recall from workshop manual), and found two faults connected with right and left light sensors, but nothing else.

To summarise: I'm pretty confident (and my wife concurs, happily), that there was no overheating or other event prior to me removing the coolant temp plug (and starting the engine whilst it was disconnected). If I understand correctly, it seems agreed that the relay can't be the problem as I am able to turn the fan off temporarily with the HawkEye. BTW if I do that operation in the right order, the fan will stay off, but the problem returns when I restart the engine.

At this point, I'm thinking I have created a gremlin deeper down in the engine's computer... I note Arthur's experience with a weak battery, and I did notice the battery voltage before start was showing in hawkeye as about 12.35 (a couple of days ago, need to re-check) - so I'm wondering if there is a link to this gremlin? Also, the car has only had one 15 min trip into town and back since this started, so maybe a longer drive may allow the gremlin to find its way out...?

I'd be happy to hear if anyone thinks I'm missing something, or if there is another idea?

Thanks,
Myles

Low voltage should not adversely affect anything long term with the ECM, I'm not sure what else has been reported but I would find that extremely unlikely.

Once proper voltage is returned all issues should go away, well after a restart anyway.

Maybe check the earthing points between the ECM and the fusebox, if the issue doesn't come back until a restart, I'd he looking at earthing.

Maybe swap the relay as well in case it is randomly sticking.