1996 Mercedes SL Power seat problem

Question edited for clarity, full make model details.
Question moved from Spanish car maker Seat, (pronounced 'See-At') to make model category.

switch on passenger seat base - MBWorld.org Forums

https://mbworld.org > ... > SL-Class (R129)
Feb 2, 2006 - It's for when you put a baby/car seat in. It keeps the seat belt tensioner in one place after the seat belt is activated.
Seat belt locking in position
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Child Smart Seat for SL ' Mercedes-Benz Forum

https://www.benzworld.org > ... > R129 SL-Class
Jul 10, 2012 - Then there is a button to lock the seat belt of the passenger seat to secure the safety seat on it and deactivate the air bag. That lock button ...
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More results from www.benzworld.org

and lastly

https://www.benzworld.org/threads/child-smart-seat-for-sl.1662040/

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you can start with fuses and relays then look at what ever jammed the seat

at the front of your seat(left side for the driver seat & right side for the passenger seat)rite at the curved corner in front of the seat beside your knees, the cloth seat has a hard plastic corner guard over the top directly in the middle of the corner in the front of the seat, and smack in the center is a up & down switch similar to that of the back seat window switch. it is well hidden & I had to have my head down there to discover it in the year2010, on a 1996 auto. the previous owner of the car did not believe me.

try to look under the seat for coins that have fallen down and got stuck in the track. it happened to mine!

seat motor is no good and needs replaced if switch is working in each position

Those power seats have two power motors. One moves it up and down. The one that moves the seat forward and backwards must have gone bad. Have it checked and replaced if necessary.

Sounds like you need to recalibrate your seat, but because you can't move it forward I don't think you will be able to. You might want to try and pull the fuse for the seat affected and see if it starts working again. If not then it might be time to replace the motors.

Tell us news (remember rated this).

If the seat is not moving forward or backward, but you do hear a click or a motorsound- chances are that you dropped in some change or other debris may be blockling the way. You might also have blown a fuse - look for fuse no. 30, which is a 30 Amp fuse.
Once you've checked all that and if the motor still does not run, then the problem may be with your wiring.
Wire colors between the switch panel and motor are:
• Fore/aft-Tan and Lt Green
• Front up/down-Dark Green and Dark Blue
• Rear up/down-Yellow and Light Blue
• Recline up/down motor's Blue and Light Green

Motor on the seat may have gone out, contacts in switch got dirty or worn, or assembly reached limit and stuck. Try sitting in it pushing back hard and adjust. If not youll need to replace switch,b take seat apart to fix or replace.

MY POWER SEATS WILL GO UP & DOWN AND WILL TILT FORWARD & BACKWARDS BUT WILL NOT GO FORWARD OR BACKWARDS. IT JUST MAKES A HUMMING SOUND WHEN TRYING TO GO FORWARD OR BACKWARD. IS THE POWER SEAT SYSTEM A GEAR SYSTEM, OR HYDRAULIC SYSTEM?