After seeing the safety benefits of turn signals mounted under side-view mirrors, I decided to install a pair on my motorhome.
I purchased two sealed amber LED lamps complete with pigtail wires. I removed the sideview mirror assemblies and drilled the necessary holes in the bottom of the arm, then mounted the lamps. I added crimp-on terminals to the pig tails and fished a set of wires through the firewall. I spliced onto the existing turn-signal wires, connected the crimp-on terminals at the mirrors and re-installed the mirror assemblies.
John Theobald, Des Plaines, Illinois