Here are instructions which describes how to wire a fuel pump kill switch into a Ranger. When this hidden switch is activated, power will be cut to the fuel pump, making it impossible for the engine to run. It is an extremely effective anti-theft device and will cost less than $10 for all the materials.

Pre-1999 Rangers without immobilizer or chipped keys (aka PATS) can easily be broken into and started in seconds using only a couple simple hand tools. I'm certainly not going to reveal how this can be done, but someone here at RPS actually had the nerve to describe the method a while ago for all to see. A fuel pump kill switch, combined with a well-installed alarm system (with a starter kill relay), a hood lock, and some kind of mechanical lock (Club or Autolock) will make your vehicle less desirable and very time consuming to steal. Of course, thieves could simply decide to use a tow truck/rollback. ;(

<<<<<<<<<<<<<<<WARNING!!!>>>>>>>>>>>>>>>>>
It is important to make sure all the connections are secure and that a properly rated switch is used. If any wiring comes loose or the switch burns out, power to the fuel pump will be cut off, causing the engine to unexpectedly shut off. If this happens while the truck is being driven, it's not hard to imagine the potentially damaging or even fatal consequences!

OK, with that out of the way, I basically followed the directions given on this dude's webpage...
http://www.courtlukens.com/Tech/cutoff_switch.htm
Even though it is for a Honda, the basic procedure can be adapted to a Ranger, or any vehicle for that matter. I used the same rocker switch he used (Radio Shack part #275-730). Don’t use a lighted switch since they can short out. Besides, why would anyone want a light to bring attention to a switch which you are trying to hide from thieves?!

Here is a picture of the rocker switch I used…
http://rsk.imageg.net/graphics/product_images/pRS1C-2160442w345.jpg

It is extremely important to use a switch rated for automotive use (25A or higher). A lower rated switch will likely burn out in short time. I spliced into the pink wire with black stripe coming out of the fuel pump inertia switch, which is located in the passenger side footwell on the firewall. This wire carries power to the fuel pump located by the gas tank. I used 14 gauge wire and blue and yellow butt connectors to make my connections to this pink/black wire. Please use a crimp tool and NOT a pair of pliers on the butt connectors! I extended the wires to the rocker switch and connected them to the switch using solder. In fact, it's probably better to solder ALL your connections. The rocker switch can be hidden anywhere at your discretion. I'm certainly not going to tell you where I hid mine.:tongue I used wire loom around where I made the splice and wrapped everything up in electrical tape to make the install look completely "invisible." I've installed the switch over 3 years ago and haven't had any problems so far.

For more auto security tips...
http://www.cars.com/go/advice/Story.jsp?section=safe&story=secLayer&subject=safe_sec&referer=&aff=pe
http://www.rangerpowersports.com/forum/showpost.php?p=894329&postcount=6
http://www.rangerpowersports.com/forum/showthread.php?s=&threadid=122378
http://forum.sounddomain.com/forum/ultimatebb.cgi?ubb=get_topic;f=9;t=001941

Here is a funny story describing the effectiveness of a fuel pump kill switch...
http://honda-tech.com/zerothread?id=999100

Have fun!

That's some good information! And that story is hilarious too!!

Added: http://www.rangerpowersports.com/tech/?p=149

Thanks!