Where is the neutral safety switch on a Mercury Villager

With the switch is unplugged, it should not start.

Could be, but there are other things involved in the starting circuit that could be the problem . The park neutral safety switch ,start inhibit relay, open in the circuit some where ! You need a wiring diagram of the starting circuit , a DVOM - digital volt ohm meter an do some testing of the electrical circuit . Go to you tube an check out some videos on basic automotive electrical trouble shooting , how to read a wiring diagram , how to do voltage drop testing . Then go here http://bbbind.com/free_tsb.html for free wiring diagrams .
https://youtu.be/GVSvA0y-peA

Neutral Safety Switch

Transmission Gear Position Switch

There are others, but they would be more
along the lines of a major problem

Try starting it in "NEUTRAL" instead of "PARK".

If it starts, then you know it's the "neutral safety switch".

BUT..........

If it DOESN'T start, it might STILL be that switch, or the ignition switch.

Sounds like u need to adjust the shift linkage or replace neutral saftey switch.

http://groups.yahoo.com/group/villagerquest/

I assume it won't crank. Are you getting power to the small terminal to the starter when someone turns the key? Can you jump power to it and get it to crank? It could be a bad neutral safety switch.

Main possibilities are the ignition switch itself, or the auto trans neutral safety switch, or a stick trans clutch safety switch.

check/replace the starter relay switch in the relay box under the hood. The relay box is located on the front right of the engine compartment. easy fix, inexpensive part if that is the problem.

check the files on this site where Villager owners help each other. I'm sure we covered this.
http://autos.groups.yahoo.com/group/villagerquest/