I got tired of not locking the Jeep because I couldn't get any of the door lock cylinders to engage the mechanism in the door (without feeling like the key was going to break off). So, I installed a cheap keyless entry kit. Here's how:
First, I sourced some door solenoids from a junkyard car. Now, I got these in about 2005, so I can't tell you what they're off of.
Second, I snooped around on the Internet and found that most local parts shops stock the Bulldog brand. Being a big fan of instant gratification, I went to my local Autozone instead of buying something cheaper online. On the same trip, I stopped by Ace Hardware for some stainless hardware.
Here's a closeup of the solenoid and its mount. The solenoid needs +12V on one lead and ground on the other to make it pop up or down, and the polarities reversed for the other direction.
I drilled two holes per door down under the lock knob near the corner.
Then I used two little clamshell clamps to hold things together. The first time I assembled this, there was slippage - the solenoid pops so hard that the clamps couldn't hold the rods. I ended up wrapping rods with double-backed tape, and squishing the clamps with channel locks prior to installation.
Installation of the controller was just a matter of threading wiring from the dash to the doors, getting nonswitched power to the unit, and giving it a good ground. I mounted the little sending unit where my emergency brake pedal used to be.
One warning - to get the reversing polarity effect, I had to provide ground to two of the wires that normally go to door lock switches (which I don't have).
Anyway, I walk away and hit the button on the fob, and BAM the doors lock. Walk back up and BAM they unlock. No worries about standing around looking like an idiot trying to get my key to work, and I know I've done what I can to keep my baby where I put her.