I have the heated, power mirrors. The driver side has not worked since I bought the truck, the passenger side just went out this year. Any hints on common failure points? This might be just the excuse I need to buy the flip up tow mirrors though.

Might ohm out the wiring to be sure the mirror heaters actually failed or is it a wiring fault in the doors. Like Wild and Free mentions about the flexing of the wires in the door might break them too.

You might try here, if you need new mirrors. http://www.discountautomirrors.com/

Sounds like a great opportunity for some towing mirrors for Christmas! -Jordan-

Might check out this thread I started a while back... http://forum.mopar1973man.com/threads/4767-WTB-Fold-Out-Towing-Mirrors-(Heated-amp-Electric-Adjustable)