My release lever did not work on my 3rd seat. After a previous post, "Fred" gave me some great help/hints on checking the problem. After I took apart my 3rd seat, I found the problem being that the release lever is not connected to the locking arm. So, when you push the release lever, it does not twist the locking arm to disengage. I'm not sure if the release lever has a broken piece (the Volvo parts dealer says it looks good) or if there is a piece that fits between the release lever and locking arm that twists the arm. Anyway, when I went to my Volvo dealer, they told me that the only orderable part was the full mechanism that you attach to the seat and that would cost $120 plus freight. I thought that a little too expensive for such a small fix.

Does anyone have any ideas? Can anyone describe what connects the release lever to the locking arm and performs the twisting action? Or better yet, have a picture/diagram? I've tried a few salvage yards with no luck. Perhaps with some help I can rig something up myself. Thanks in advance for any help!

It's broken? If you have it off you can see that there's not much to it but if it's physically broken, I doubt there'd be a good permanent fix unless you can creatively "rig" something.
It moves very slightly so if it's not really broken, then perhaps it's just not moving correctly when screwed into position? Are any parts of it binding or catching on something when in place? Was some carpet removed, cut out under the area where the release lever is because cutting that out is part of the instructions and if not done, the lever will bind and not release well. If it seems to be binding, silicone spray often helps. The complete assembly is also adjustable side to side as you can see w/o the upper seat back installed so you can temporarily install that section w/o the seat back and experiment with adjustments until you get it right if need be. I usually don't have too many problems with those but on occasion one might need more attention than others.
Hope this helps?

I'm not convinced anything is actually broken. What may be more of the problem is a piece might be missing that connects the release lever (the part behind/under the headrest) to the locking arm (the piece with the notches that locks into the back seat).

When I had it apart and it was locked in, I was able to take a needle nose pliers and slightly twist the locking arm and it would release. The release lever isn't connected any way to the arm, it is just floating free. That's why I'm not sure how the release lever connects to the locking arm.

The release lever has about a 2 inch "U-Shape" at the end and I am assuming that should be connected to something that makes the arm turn slightly for the release or is something broken off the release that connects it to the arm. I appreciate your time in helping with this!!!!

w/o seeing one in front of me, I can't presently picture those details but I've never seen one missing pieces. If you're convinced that yours is missing something, I'd think that a "nice" dealer parts guy would be willing to remove one from a kit temporarily so that you could at least look at a new one before spending $120 on that part. I know that it's only sold as an assembly, no individual small parts available for that larger part. Just a suggestion.