Mile Markers RF wireless winch controller has been on my jeep for about a year now. It consists of two parts: The control/relay box, and the remote fob. The control box mounts inside the vehicle. It has an "enable" switch on the front panel and a connector on the back. You connect to the existing wired power junctions under the hood. The unit works in parallel with the hand-held wired controller -- you can use either.
Experience shows that this unit has one annoying drawback: the receiver does not seem to have a great PLL circuit, so I find I have to tune it pretty much each major outing. The second photo shows the screw inside the unit which must be adjusted if yours seems to not work or have poor range. It's a real pain that shouldn't even happen.
Even so, once adjusted properly the unit will work from over 250 ft away!