How does the rear seat of a 2003 s type haguar fold down

The second row is folded by first pulling up the rear of the seat cushion and folding up 'til it's behind the back of the front seat. Then the back of the seat folds down where the seat cushion was.

The third row seats have several levers that are numbered in the sequence they are to be operated. First fold the seat back down on to the cushion and then flip the whole seat up 'til it's vertical and latched.

This is described in the Owner's manual if you can find one.

First fold down the rear head restraints by pressing the button on the side of the head restraint. Now you can fold your seat down in either of these two ways:
1. Pull the button on the top of the seat to unlock it from its position; you will notice a raised tab when the seat is unlocked
2. Depending on the type of seat you have, you can lower it by pulling a lever on the right side of the rear cargo area.
Remember, the seat belts should not be fastened when you attempt to lower the seat.

FYI- I'm taking a shot at this one based on my 2003 Montana so take it for what it's worth.
My van seats have a very small level on the drivers side of each seat. Pushing the lever down allows the seats to fold down while pulling the lever up allows them to recline. There is also a small ******** the back side of each seat which when pulled allows them to be folded down.
Hopefully your 2003 Yukon seats are similar to my 2003 Montana seats and this will work for you

Lift up on the rear seat cushion and fold it towards the front. Now pull the lever and fold the seat down.

Open the back trunk, look near the top of the trunk, and pull the two black levers. They have a seat folding down symbol. That will release the locks to fold the back seat down.

THE SEAT RELEASES ARE IN THE TRUNK IN THE AREA WHERE THE SPEAKERS ARE NEAR THE EDGE OF THE TRUNK OPENING.

There is a latch located behind the head rest on the rear deck area of the car. Good Luck

If car has fitted option of split fold rear seats, open the boot & on underside of parcel shelf near boot hinges there is pull handles

get your dealer to replace the seat belt, depending on age, should be under warranty. Belt is defective. I have a g 2003 vue, and my dealer replaced the belt for no charge.

I had the same problem on my '03. The seats would not fold down using the latch release as I had always done. So I tried a combination of pulling up on the side latch AND the top latch and the seat folded down. It really doesn't FIX the problem but circumvents offending  defective part. I will use this method until it doesn't work then I might shell out the $$$$$ to the dealer.