My '03 4Runner was having the issue where I could unlock the doors but not lock them with either the key fob or power locks. I searched and searched all over the internet and found that a possible solution was to replace the fuse box/control panel under the driver side dash.
My solution does involve the control panel under the driver side dash, but does not require replacement. See, I noticed that if I pushed the control panel/fusebox in quite hard while working the key fob and/or door lock switch, IT WORKED! So, my silly solution was to insert a t-ball (regulation size) between the fusebox/control panel and the paneling closest to the driver on the top side of the fusebox. IT WORKS!! A regular baseball didn't work, prob. b/c it was too hard. A tennis ball didn't work, prob. b/c it is too soft. BUT, the Tball worked! Just the right balance of firmness and softness.
Glad I didn't spend $500 for Toyota dealer to replace!
Hope my son doesn't miss his t-ball!!