Bought my 2005 Sequoia about a month ago, 257K. The rear hatch would not open. War #1. I know this a common problem on the 1st gen Sequoias, possibly newer models as well. Purchased a new latch, somehow they shipped two of them to me. Great, now I have a spare. 

While getting everything removed and prepped for the new latch I found out the license plate bulbs were blown. War #2. Replaced the bulbs. Still didn't work. Checked all fuses and looked at all the wiring, all good. Now what? I refused to give up. There is a section of wiring that makes a 180 turn as it goes inside the hatch panel, perhaps one foot from the bulbs. I took off the black shielding and the wires were completely disconnected. I reconnected them with some solder and heat shrink wrap and they worked!

All right, making some progress. Then I installed the latch. It took a while because it looks like someone has attempted this repair before. Several clips were broken or missing. I did the best I could, replaced some clips, and it all came together nice and tight. The latch worked. Awesome. 

A few days later the latch stopped working. It was stuck in locked position. War #3. I ordered the latch actuator and it arrived today. The actuator came with a new cable, this is important as the original cable is likely worn out. I had to fight hard to get the hatch open, pulling on the cable by hand, WD40 on the outside of the actuator (the flexible metal hose line on the can of WD40 came in handy here) and some kicking. Finally it opened up. Phewwwww, if it didn't then it is cut the striker time which is more parts and labor. Took everything apart and reassembled it with the new actuator. I tested the latch before I installed it and of course it worked. Once installed it didn't work, wouldn't open. Maybe the ball end of the latch cable fell out when I attached it? I detached the cable to the latch and reattached it (it is a tight fit!). Now everything works! 

Things I learned:

1) If you keep replacing latches then it is time to replace the actuator and cable too. 

2) If replacing the license plate bulbs does not work, trace the wiring about a foot from the bulbs to where they connect to the vehicle on the inside of the hatch. You will need to remove the black shielding to the wiring, else you won't see any damaged wires. 

3) You might get lucky with some WD40, kicking, and manual cable pulling if your hatch is stuck in the locked position.

4) The actuator is in a bad spot. Its going to get a lot of exposure to the elements. Not a bad idea to lube it up every 6-12 months. 

5) Total investment was about $80 and almost 8 hours of my time. But I split it up over several weekends and it sure beats what the dealer will charge you.

6) There are several you tube vids out there that show how to replace everything, they were invaluable. 

It was war, and I won! And you can win the war too!!!