When I installed this switch, the original one with the motor worked. Still, I figured better sooner then later. The new solid state turn signal I got under the dash helped the original part work much better. Yes, the new one does in fact plug in....mostly.
That slim blue wire will simply not stay put in that socket no matter how much electric tape you try to put in. I found a very small stainless sheet metal screw and held it in that way. It would be better to include an optional quick splice terminal such as one of those Dorman ones that Autozone has in case it won't stay put on its own.
The bulbs can also become unseated easily and may not all light up when you put it in. Take each bulb out. Make sure it isn't burned. Make sure its seated in the socket and that the socket is seated in the harness. Taking off the harness first makes it easier to change the bulb. Lots of fiddling around is required. One side was fine, the other kept acting up until I got the bulbs seated JUST right.
One other oddity that I noticed is how the hazard blinker behaves. If the turn signal is centered, neither left or right, and you put on the hazard blinker, the middle 2 lights flash only on each side. There is nothing wrong with this. The bulbs are symmetrical and street legal that way. If you put on the hazard blinker and the turn signal rod is either left or right, you'll get the full effect of the flash sequence going down on both sides.
Maybe one setting is for driving in fog and the other is for actually being parked beside the road, but the owners manual (I have the original 1968 manual) says nothing about this whatsoever.