Can anyone give me some advice as my exterior mirrors won't work on the heated side of things !!!

I have looked at the fuses & can't find any blown 1's, also i have checked the mirrors & found that although there is wiring there, there is no electrical feed even though the car doesn't have heated mirrors fitted ????

If anyone can help with this problem i would appreciate it as its so annoying, i'm fitting new heated mirrors buti need the feed to be there to marry up ???

Thanks, Colin.