DIY Doctor UK DIY Forums

I have a 2 way 3 switch light in my hallway that I am trying to convert to a 2 way 3 switch dimmer, however since reconnecting to the new switch either the kitchen light s or the living room lights dont come on. I dont have a modern consumer unit just the old fashioned fuses. If I change the fuse position for the downstairs circuit I get either the landing light on its own or the hall light and the outside light. There are 3 cables the core colours are:-
red,blue,black and one white core.

I have tried reverting to the old switch but even that doesn't work right and works like the new dimmer because I am now very confused can anyone help?

You say you swap two fuses and the fault swaps so you must have blown a fuse!
Old switch works like new dimmer! You must have swapped something so sorry only one safe way. Get someone in to look at it.
Yours Eric