There is a wiring kit available. I'd have to google it again to find the link, but it is available. It looked too involved for my taste: pull the door panels; enlarging holes for additional wiring harness; splice in the new wiring harness. Once it was all spliced in, the mirror's turn signal became a clearance light.
Personally, I have no desire to cut and splice any factory wiring. If I was simple plug and play and easily reversible, I'd maybe do it.