Mrstruan

Hi folks, new to the forum here. In have a 1999 996 Carrera 2 which is causing me some angst. Last year, whilst the car was elsewhere, it was connected to a battery charger with the keys in, which threw up an airbag light. The code was 53: drivers airbag sensor. I subsequently replaced the sensor with a used one on eBay and the code cleared and gave me a few days driving to get through my MOT. The light came back on, I can clear the code with my Autel 619, and the code stays off when the car is running, however when I switch the car off and remove the key, the next time I start the car, the code is back. After a whole year of accepting this fault , I decided to try and fix before the next MOT. I removed the current airbag control module (996.618.219.00) and replaced with a replacement control module (996.618.219.00) from eBay. This was worse and gave a whole host of new codes which I couldn’t clear. I purchased another module (996.618.219.01) and another used airbag sensor for the drivers side from an eBay breaker. The new module seemed to be ok for a moment when installed and historical codes cleared however the drivers side was still recognised. I have since dismantled the drivers side again to get at the sensor and fitted the “new” eBay sensor, only to be met with the same condition I.e drivers side sensor error which can be cleared but comes back when you take the key out and turn the car on again. Questions: can the wiring to the sensor go bad? is there a way to test the sensors? is there anything else this could be apart from unlucky with parts from eBay? to me, the fact the code clears and stays off suggests it’s not necessarily an issue with the sensor, as the last time the sensor was broken, the code would not clear but I’m at a loss as every time the car is switched off, the code is triggered. Any help or suggestions would be greatly appreciated. thanks Struan