It like anything it can brake after a week or a year, I don't have link or nothing but if you take the top off the pump and remove the old switch ( it's the little black box with the 2 metal prongs on it ) Maplin do one with exact same size fitting on, only difference is the Maplin one comes with 3 prongs on it, I just snapped the spare one off and had a perfect fit.
I think it is £2.49
Ps.
This was for a shurflo pump, I haven't done anything with this vyair weapon am using at the mo.
I just gave a lad 2 shurflo pumps that broke, am not up on all this electrical stuff so they were no good to me, I told him to do as above and he rang me yesterday thanking me for the pumps and do I want any money for them

, they both working for him and he's happy as a pig in

?
Be careful the spring will go .............. Boing and you need to see we're it comes from haha
Good luck
Matt