i would recon you get a spark to do it,but,if you want to change it yourself,heres how,
turn off mains,remove the two screws from switch unit,you will prob find the black(blue)wire is burned out,rewire it as you find it,the supply is marked,guess what,supply,the output is marked load,(shower feed)make sure that you cut off any burnt wires,(that fresh wire is wired to switch,if the spark has left enough cable)make sure that you connect the two earths,try not to use the switch to turn off shower,its ment to be an isolating switch,use the controls on shower to turn on off
,gts, September 2010
