Recently bought a set of aero power mirrors that were in great shape for my 91 vert. The wiring was cut and no big deal was just going to splice them on to my factory harnesses. Well went to do that and realized that the aero mirror are 4 wire and the factory harness is 3 wires. Looking up the factory wiring diagram hasn't helped and I can't find any information on the jdm mirrors. Messing around I was able to get the up and down function working but not left or right. Just looking to see if anyone has experience with these and knows how to wire them up or if I'm just screwed on getting full function out of them. Thanks.

 

I'd think "outside the box" for a second.
Personally I'd Look for Guys Selling the mirrors that had them On an FC and private message them "nicely" and ask for wiring help or tips!
most lads on here are more than willing to help.