Can you post the model number of the appliance please.
Also is it you are replacing the regulator and the one you have now is different to the one thats on yours?
If so what the part number of the switch you have?
Now how many wires do you have?
Can you post a picture of the wiring on the old switch?
Ok basically the wiring conversion is as follows.
P1= Is the live feed in.
4= is the neutral feed
2= is the load which is the feed to the heater plate.
S2 or pilot= is the pilot light whichs is the mains light on the control.
Now to work it out you need to follow the wiring on this.
To find the pilot light will be easy as follow the wires to the light.
As to the live and neutral feed one would assume the live is the brown and the blue is the neutral.
So this just leaves the load feed to the heater which is the other wire which will be either the black or red wire.
The reason i ask for a picture was because i thought it was a conversion switch which is different from the old one.
So thats the wiring for this so its a case of following the wiring to see which is which as the wiring diagrames on these dont list the colour of the wires im afraid.
Let me know how it goes.
The wiring i listed above is for the regulator you have just brought.
Try and wire it up that way and see if that works as i assume the way you have wired it now isnt working?