Went to open my left rear door and the it won't open. The handle pulls up freely from the outside but it doesn't have that "catch" feeling like when it worked properly. So, here is my question -- What could be wrong, and how difficult is it to remove the inner door panel to get a looksee at the innards? Would hate to have to take it to the dealer and pay out my ass for perhaps something simple.

Whitey

 

Most doors have a small bar that hooks on the door handle. See if it came loose or broke. I have not taking the door a part on a 4 runner so i can"t help there. good luck

 

You might have already looked, but is the child safety tab locked? will it open from the inside?. Just a thought.

 

I've had the door on my '90 opened up, you will probably have to get the door open first, to get the inside panel off. There are a couple of rods that connect the handles and locks to the to the door catch, the rods are connected to to the locks/handles/catch with small plastic clips, one of those may have broken or come free (if it's not the child locks that is).
It's not that hard to check out,,, the worst part is probably getting the panel off without breaking any of the plastic clips that hold it on. Most will come off with a gentle pull, and there may be a special tool available, check your local parts store. I didn't use a tool, ended up breaking a couple of clips, but they are an easy find at the local wreckers.
Of course electric locks are probably going to be a completely different deal, I don't know anything about them though.
Good Luck