Hi. A4 B7 Auto. Ruining my life...

History:
fans not working-> replaced control module (ebay) -> one fan starts working
fans not working-> replaced fans -> both fans working then stopped and car overheated
fans not working-> replaced control module (ebay) -> both fans working

Currently:
Drive car, stop car, get out, come back to get something, open drivers door, close drivers door, fans start, don't stop, drain battery

No water in ecu box and relays looked fine.

Have ordered new relays, have ordered new grey 2pin temp sensor, will soon be replacing t-stat.

So what I want help with is understanding whats causing the fans to kick on when I open the door. I know the fuel pump primes when I open the drivers door, but does something kick the fan on too? Should I suspect the control module being the cause of this? I would have thought the control module only goes one way and that it wouldn't by itself trigger the relay to fire the fans...

Should I look at replacing anything else?

Any help would be appreciated