I have a 2002 F250 CrewCab 4x4 7.3l with the small non-heated power mirrors. Have purchased a set of 2000 power,heated telescoping mirrors which included a jumper harness that was to hook mirrors up(told they where supposed to). The jumper seems to be for trucks 99-01. Wondering why can't use plug end of old mirrors on new. Old wires on driver side are red, blue, and either black or brown. New mirrors are red,blue,and yellow. Also have seen how to hook up heated part off window power switch; but both wires on new mirrors are same. Does it matter which is hot or ground? NEED HELP!

 

Heating elements and motors usually draw a lot of power. I would assume a truck originally equipped with heated mirrors would have seperate fused circuits with heavy wires running out to power the heaters.

And they also probably have power relays on timers, so a small switch can be used to turn them on, and they probably cut off automatically after a certain time period. At least that's the way rear window defrosters work.