I have racked my brains out trying to come up with something that would work for 2 weeks on and off and yesterday finally made the part that works flawlessly in the rear doors without hitting the window or door shell/skin. I'm just curious how Ford did it as I could not find a picture or drawing of it anywhere.

The interesting thing when I was doing research on this initially is that the parts catalogue shows only 1 part number for '66 door latch mechanism. Where as the '67 and '68's have different part numbers for electric locks (must be integrated switches) which makes me think the switches bolt onto the existing holes in the '66 (and probably '65 by default) door latch assembly. Anyway that's what I did was make a bracket to hold the micro lever switches onto the door latch using the existing holes (no door latch molesting required).

Regarding convenience lock and ajar lights, it wouldn't surprise me if Ford used a cheap copper/beryllium strip isolated on a nylon base that used a self tapping screw to hold it in place and it grounded on the moving metal parts of the door latch to activate (kind of cheesy in my book because of old grease and oxidation causing connectivity problems in short order). Even the parking brake switch/light (same thing) gets kind of sketchy in operation unless you use it constantly.

OK, well I am a knob, I read the parts manual wrong and given some pictures it seems one part of the Ford Parts manual is in error on the front door latches.

Since I tend to bumble on, picture time....

Here's the illustrated parts guide for the front door.

This is where I was an idiot, I was looking under section B instead of A. But notice there is no call out for separate latch part numbers for vacuum locks. There should be. Evidence coming up.... But first the legend.

A is full size Ford, B is Fairlane, Torino and Falcon.

Rear door latch illustration.

Now there are different part numbers for latches with vacuum locks and without. Interesting how '68 has its own latch mechanism.

Now onto the really interesting part. Some pictures of the front and rear door latches have an extra plate affixed to one of the catch mechanism tooth cams. The latches I have (LTD and one spare set) have no such plate to ground the ajar contact.

Here are the front and rear door latches. No plate on them. These are the spare set of '66 latches, the '66 LTD's are the same way. So clearly someone FUBAR'd the parts manual because the front latches are different in '66 for vacuum locks.

OK I don't feel so bad now in spending so much time on this. Anyway, concentrating on the rear latch I came up with this CAD model after several prototypes.

Here's the final one, a previous attempt on the left. The window clears this (just) and it fits fine in the door. I still have to put on a Deutsch connector and non-sticky tape wrap the wires.

Nice part about this dohicky is that it screws right onto the latch using the existing holes. The tricky bit was locating the door lock detect switch on the right angle so even taking into consideration backlash there is no false triggering whilst exercising the handle actuator.

Cheers