EMPTY TERMINAL BOTTOM OF 67 CUDA HEADLIGHT SWITCH

if the switch bolts to a metal dash
you don't need the ground tab, because it grounds through the screw in metal collar and the spiked metal tab that stops the switch body turning in the dash hole

this, i think you have acknowledged

if the switch bolts into a plastic insert in a dash pod, that has no metal backing or a metal backing that does not cover a mounting screw hole and hence, no ground....!
run a wire from that that ground tab to a screw in the back of the dash

switch is multi use for plain jane metal dash base model, and fancy pants top of the range cars with a dash that looks like a jumbo jet

if you have any other extra connectors on your switch over and above the number of wires you have, or places in the special connector block, then you have the wrong switch

and the same if you have a lack of connectors on the switch...
subtle differences of the few connectors in the middle of the switch between models regarding what is switched to 12 volt and what is switched to ground
wrong switch there will be something that doesn't work

and there are numerous versions of this switch, they were still in use in 90s jeeps
and they are not all the same you need a year and trim level appropriate version.

the depth of the switch also differs between models of switch this is a function of the metal bracket and the size of the variable resistor set up for the light dimmer. if you are a bit short in the shaft of your knob :) it can't reach the socket in the dark depths of the switch :) and will not engage. if your knob shaft is too long the knob sticks out too far all of the time :).
However it engages perfectly well, and you will have to press on the little button, to get it out again, but it looks kinda wrong..



You need a switch with the right no. and position of connectors regardless of if it has the earth tab or not

the fuse box will always, unless your car has every option going, have a few connectors on the back or even a fuse space that is not used. this shouldn't worry you
the manual for your car will have a fuse box diagram labelling up fuse size and the wires

fuse box is split into 2, hot (12 v) all the time, and hot when key in any position other than off (acc.,run,start)

the connectors on the back will be split into 2. with the always on 12 volt wire or a switched 12 volt wire as input, at their respective parts.

the other side of the fuse box has a single connector for each fuse, some may have a piggyback double wire onto that single connector but thats still all OK
and or course any unoccupied fuse bay will have no wire to its connector

in many cases there will be one unused fuse holder it may have a fuse in it.. handy place to keep a spare, but it won't have a wire from it to anything.

Most A bodies have an outlet that splits into 2 via a plastic manifold or 2 outlets on the heater box to cover 2 vents in the dash, having 1 disconnected just means the air takes that path rendering the vent that is connected ineffective at demisting the screen

a place that does piped-air heating for mobile homes and caravans will have a foil and paper tube in the correct diameter for you to fix up the other vent. cut to an, a-bit-too-long, length, with razor sharp craft knife and it should stay pressed onto the outlet and the back of the vent, of its own accord

Dave