Back seat left back seat will not release and go down,

Assuming yours is the third generation Cavalier, (1995 to 2005), the seats can only be dropped from the trunk. Open the trunk lid and look up at the underside of the parcel shelf. There should be two straps hanging side by side. If you pull the left one the left seat should release and the right one for the right seat. You should hear it release as you pull it. Sometimes you have to push Gently on the back of the seat as you pull the strap to get it to release. Swing the seat belt straps out of the way and the seat should fold almost flat.

Pull the release straps located in the trunk. The right strap operates the passenger's side rear split seat. The left strap operates the driver's side rear split seat. Fold the seatback down from the inside of the vehicle

Releases in trunk is of no use: no tension/connection therefore cannot engage/pull the cable to release seat to go down. The lever on lower right side of rear right seat won't engage, just flops about.

I just ran into the exact problem with my 2004 Suburban. Once I got the seat to lay down all the other mechanisms worked as they should and I could get the seat in and out as usuall. I found this post below which explained how to get the seat down. Wish I could take credit for figuring it out on my own but I can't.
"After working on it for a couple of days here is what I did to remove the 3rd row seat.
On the rear lower right and left side there are plastic covers, if you push the seat material forward a little you can see a hole where a nut holds it on, remove the nut. On the left side pull back the plastic cover and you can see the wire and the lever that releases the seat. With my foot holding up the #1 release lever on the right side I used an open end wrench to push forward the left side lever and the seat folded down.
I then used the #2 and #3 levers to remove the seat.
To view the whole cable, open the lower seat cover, it is an overlapping plastic clip, My problem was a loose cable, similar to a brake cable on a bicycle, after fixing it I have had no problems."
To remove the nut I used an 8mm socket wrench. My problem was not a loose cable but the #1 mechanism wouldn't pull up all the way, I'm guessing because that left side locked in out of order. I pushed that left side lever down with a hard tool and had my 5yr old daughter pull up on the #1 and the seat folded right down.
Hope this helps if you havn't already gotten it fixed.

To fold-down rear seat on 2007 Chevy Malibu, follow these steps:
1. Open the trunk
2. Pull on one or both the handles located on the upper side of the trunk
3. The handle located on the driver's side will unlatch the bigger part of the read seat
4. The handle on the passenger side will fold down the smaller portion of the rear seat.
5. Once done, you will have a seat that's nicely folded down.

I had the same problem with our 2004 escalade. I found a small rock blocking the back left seat post from engaging. after I moved the rock out, the seat engaged properly, and folded down aok!

The hood release is on the lower left edge of the dash, if your sitting in the drivers seat, lean down and feel the lower left edge of the dash with your left hand. You'll feel a small square plastic flap and pull straight back on it. You should then hear the hood release pop free.

If you have rear seats that fold down you can access the latch mechanism from the left side rear seat....if you are flexible. pull the corner of the seat forward to allow your arm to slide in behind. about 14-16" in, feeling up inside the trunk you can feel 3 quarter size holes in the sheet metal. The second hole has the cable release arm. stick your finger up there are pull towards you. this will release the seat allowing it to fold down. Crawl into the trunk. there is a glow in the dark release handle on the inside of the trunk lid to open the trunk.

The pull down on a 05 is in the trunk. There is 2 loops on the underside of the upper trunk body drivers side. Pull loop and push seat forward from trunk until it releases. Left side loop is for left side half of seat and right is for right.

There shouls be 2 straps inside the trunk at the top. Both on the driver side but one is for the left side and one for the right side seats. Pulling on the straps releases the 'lock' that should then allow you to pull down the seats from the back seat area.