I have replaced my expansion tank a few times now ! on my fabia but they don't cure it for long ? so i have replace it with a new tank with no sensor in it , but the warning light and beeper still come on ,, any ideas why ? and can i get rid of it please ? 

Not sure what you mean by a tank with no sensor in it. I thought they all had sensor probes in them. If there are no probes in it then it's not surprising that the warning light is on as it needs resistance of the probes in water to keep it off.

I brought a after market tank with no senor in it 

Just short the contacts in the plug.

44 minutes ago, gijive said:

I brought a after market tank with no senor in it 

 

I see. Yeah, just join the two plug wires together then.

Ok thanks that simple then 😎