my liftgate lock has decided that it's going to do it's own thing. It only unlocks when I hit the button about 20% of the time, if that. Usually that's if I lock and unlock 2 or 3 times in rapid succession. It almost never locks it's self either. If I recall it did do this a few years ago too for a couple months and then stopped.

I'm just a little more worried now because someone stole stuff out of my truck in my driveway friday night when I left the drivers door unlocked for a couple of hours.

 

Try a little wd40 in the lock mechanism. Might be sticky.

 

Sometimes the bars that attach to the lock tabs (mechanisms) are loose/bent. Could also be the plastic housing is cracked around where the bar attaches to the lock pin. Try manually doing it with the key. if that works then its an electrical problem.

 

key works fine every time. Window goes up and down fine at the switch and the alarm will still go off if you unlock with the key and open without turning the alarm off.

 

I found that there is a safety feature on some models. Make sure your rear wiper is fully seated back into its holder, otherwise you can't open the rear window. Mine locks automatically when I close the window.
-Do you have a separate lock switch for the rear?
-What model/year do you have?
-Sounds like an electrical problem.
-Could be a worn switch contact.
-Could even be a worn actuator/motor.

 

I made sure the window was all the way up and the wiper looks like it always does.

When I get a change I guess I'll take the pannel off the interior.

 

Cycle the wiper to make sure, it only needs to be off a hair.

 

I had to replace a piece out of the liftgate last year, and things can get messed up in there. The panel is not hard to get off, but once it's off, you should be able to see the problem. The inner piece of the handle broke on mine, so I just bought one from someone who was parting out their 4runner in the classifieds section. The wiper shouldn't have anything to do with the lock. Remember that once the panel is off, you will have unplugged the electric lock, so you may have to fanagle something to watch it work (or not).
Good luck!

 

The wires between the body and the hatch (at top, under rubber boot) break sometimes. Sometimes it's just enough to cause an intermittent problem. Were it me I'd check there before I pulled the panel off just because it's super easy to do and that's where the wiring gets the most flexing. After taking 30 seconds with that is when I'd pull that panel if I didn't find the problem in the first spot. One screw holding the grab handle, the rest of it just carefully pops apart and then it's hooked to the top at the window, much like a door panel. I've got pics of what the inside looks like real close to the end of my build thread- though I wasn't working on the same problem so it's not as specific as you might like.