Passenger seat back will not move either direction

Question edited for clarity, you forgot Herr. Benz.
Question moved from Spanish Car maker category Seat, (pronounced See-At) and nothing to do with car seats.

Can you hear the motor running? It can only be 5 things

Fuses
The Switch
The Motor
The linkage and drive
The Power Seat Module

Look underneath with light and mirrors. Or remove the seat to look.

Help in the link

https://www.google.com/search?q=mercedes+cl550+seat+lift+not+working

..

Question edited for clarity and errors.
Question moved from Seat, (Spanish car company) to PT Cruiser.

You would be better to fly, or put her in the back seat with lots of pillows and use the centre lap strap as a seat belt.

If you pull the seat all the way forward and remove the headrest, you should be able to see the maximum recline, but electric seats have a stop on them.

Swingit into a partstore for freehelp. They may hav some lube for it allso

First is there a lever on the side of the back if not did it ever recline? If it did used to recline and you can lift the lever all the way up try to bring the back forward and then see if it will go backwards.

This one is pretty easy to figure out. Your seatback isn't working correctly. Okay, I'll grant that my answer may seem pretty obvious, but, it really isn't, please hear me out.

When you yank on the handle the pawl that engages and locks the seatback into position, so that it won't move, is removed from its receiver. In this mode, the seatback moves freely back and forth as there is nothing to prevent its movement back and forth. You use this movement to find the exact seatback angle for you and when you have, you release the handle and the pawl is reengaged and the seat is locked. (There are various safety features involved that assure you that your seatback will remain locked in position. While the pawl and receiver are quite sturdy, you cannot depend on them alone in a crash. So, there is at least one interlock device that engages when the pawl goes home. The interlock helps to "rigidize" the seatback so it doesn't move.)

What is happening in your car's case, though is this, the interlock may be broken so that even if the pawl releases from the receiver, which it apparently is doing, your seatback remains locked because the linkage between the handle, pawl and the interlock is not working. You will have to have the interlock (it could be that device) and its linkages repaired before the problem will clear up.

If it will move in every other direction I would start by looking under the seat and check down in the seat trac for something lodged in it way.

I have a 95 960 wagon and my seats have circuit boards

You have to check the power to the recliner motor. If there is power, then replace the motor.

The set on the passager side of my 88 420SEL wont move up, and it make a noise about every 15sec like it is trying to move.

You can move the drivers seat back by turning on the power, getting in the seat and position your feet firmly on the fron flor with your back firmly against he seatback, and then engage the switch pushing back - while pushing like hell with your feet. You can actually hear the seat drive shaft turning while the seat moves back. The principle should be the same for moving forward, but pressure would have to be aplide to the back of the seat.