Memory seat does not fully recline

Power Recliner
The driver seat has an electro-mechanical backrest adjuster. The backrest adjustment switch is located on the side of the seat cushion side shield and is part of the seat control switch. The recliner motor is mounted to the backrest frame. Power recliners and motors are only serviceable by installing a new backrest frame assembly.
Does yours have Driver and Passenger Power Seats Without Memory Or Power Driver Seat With Memory ?

B1666 Seat Driver Recline Motor Stalled On-Demand If the motor does not operate, Go To Pinpoint Test L . If motor operates, Go To Pinpoint Test M . Take it an have it check !
Does your

The cable that runs the seat back has twisted so many times it has disengaged itself from the seat back transmission. Pull the upper upholstery up and remove the cable housing from the transmission. Remove the metal end by trimming it off . Remove the piece of housing from inside the end reinstall the end, crimp it just a little and put it back in the transmission use the button and return the seat to the upright position and use the memory buttons to keep it positioned there.

Remove the seat from the floor and re-connect the cable that drives the seat from the end of the motor. If cable is broken, replace it.

You do not say what design 3 series; but for E36 with electric seat adjustment, Odometer Gears (link below), makes replacement gears for the electric seats for approximately $40 each. This is the part that typically wears/breaks for seat reclining.
BMW-US E36 Driver's Seat Recline Gear/White
BMW-US E36 Passenger's Seat Recline Gear/Green
http://www.odometergears.com/products/BMW/3+Series+E36+90-00/26

It sounds like the inside of the recliner knob is stripped out. If you go to your local GM dealership and give them your VIN number they can order you a new one. Here is the removal and installation directions.
Driver or Passenger Seat Recliner Handle Replacement Removal Procedure

1. Use a flat-bladed tool to remove the plastic center cap from the center of the recliner handle.
   
   
2. Pull the recliner handle off the shaft.

Installation Procedure

1. Install the recliner handle on the recliner shaft.
   
   
2. Push the recliner handle firmly onto the recliner shaft until fully seated.
3. Install the plastic center cap into the center of the recliner handle.

Hope this helped please hit the accept button and positive feedback is appreciated.

electric or manual?

The first place to start would be to have the dealer or someother qualified repair shop , that has a professional scan tool read DTC'S - diagnostic trouble codes in the driver seat module ! The seat adjuster motors are controlled by the driver seat module through the adjuster motor control circuits. In an inactive state both of the motor control circuits are grounded within the driver seat module. In an active state the driver seat module switches the appropriate motor control circuit to battery positive voltage. The direction of the adjuster motor rotation is determined by which of the motor control circuits is switched to battery positive voltage while the other remains grounded. During adjuster motor operation the driver seat module also monitors the current flow through the motor control circuits.
DTC B1770, B1775, B1780, B1785, B1790, B1805, or B2415
B1825 , B1850, B1860, B1960, B2355, B2365, or B2375
B3962
Memory Seat System Components
The memory seat system consists of the following components:
• Power seat switch assembly
• Memory recall switch assembly
• Horizontal adjuster motor
• Front vertical adjuster motor
• Rear vertical adjuster motor
• Recline adjuster motor
• Driver seat module
• Driver door module
• SEAT 30A circuit breaker
Memory Seat System Description
Battery voltage is supplied to the driver seat module through the power seat circuit breaker. The driver seat module supplies the seat adjuster switch assembly with a battery positive reference voltage. While the seat adjuster switches are in an inactive state the switch contacts are closed to the adjuster switch ground circuit. When a seat adjuster switch is pressed to an active state the switch contact is closed to the reference voltage circuit. Battery voltage on a switch signal circuit indicates to the driver seat module the switch status is active. Each seat adjuster motor is controlled by the driver seat module through 2 motor control circuits. While the seat adjuster motors are in an inactive state the motor control circuits are closed to ground circuit contacts within the driver seat module. The driver seat module operates the seat adjuster motors by switching one of a motor's control circuits to battery voltage. The seat adjuster motors are bidirectional and the direction of adjuster motor rotation is determined by which of the adjuster motor control circuits is switched to battery voltage while the other remains grounded.

Memory Set/Recall Operation
The seat adjuster motors are equipped with internal position sensors. The adjuster motor position sensors are monitored by the driver seat module and are used to determine the seat position when storing or recalling memory settings. The horizontal, front vertical, and rear vertical adjuster motors use hall effect type position sensors. The hall effect position sensors are supplied with battery positive reference and ground circuits from the driver seat module. The position sensor signal circuits are supplied battery positive voltage through a resistor them monitored within the driver seat module. During adjuster motor operation the hall effect position sensor provides a single pulse for every revolution of the adjuster motor shaft. The driver seat module counts the pulses from the position sensor signal circuits to determine the adjuster motor positions when storing or recalling memory seat position settings. The recline adjuster motor is equipped with a potentiometer type position sensor. The recline motor position sensor is supplied with it's own 5-volt reference ground circuits from the driver seat module. The recline position sensor signal circuit is referenced from ground within the driver seat module. The signal voltage monitored by the driver seat module ranges from 0.39 - 4.58 volts and is determined by the wiper location on the resistor within the recline motor position sensor. The recline motor position sensor signal circuit voltage level is used by the driver seat module to determine the seat recline position when storing or recalling memory seat position settings.
The memory recall switch assembly on the driver's door provides inputs to the driver door module. Battery voltage is supplied to the memory

usually not. seat is electric and adjusts to extent allowed by that. Passenger seat has a back release on it though.

I don't remember which knob adjusts that area for the seat but if it's like the one I used to own, much older model, it had a turn knob on the side of the back rest that you had to actually turn to get it to do that recline position. Look at your seat and see if it has a large knob on the side of the back rest and if it does, turn it until the seat reclines. I think it does. but not sure. if it doesn't then look on the side of the seat by the door for a lever there to see if that is the lever to make the seat recline. Vw has more than one knob most of the time. you can also check your owner's manual for seat adjusting and it should tell you something.

If it's anything like seats in GM's there is only one motor for each "function". They use a small gear box, with shafts and gears to distribute the movement to both sides of the seat. You will see a few motors under the seat also. Depending on how they made them, the recline motor may be under there too.

The cost will vary, and that's only IF a replacement part is available. Sometimes you have to get awhole new seat (some leather Caddy seats are close to $2500 EACH - ouch). You can always scour ebay (just do a search for "concorde seat" - theres actually a guy selling the entire lower rail assembly as i'm writing this)

Some seats have a factory unzippable cover. This may or may not allow you access to poke around in there.

I would check for any obstruction caught up in the pivot of the seat or near the area where the shafts / gears meet the tilt mechanism. It could be anything really, but coins tend to be the majority of the culprits! I've found that trying to lay on your head to find them is a pain, and you always miss something. It's easier to unplug the power to the seat, take out the 4 bolts, and turn the seat upside down in the driveway and shake out whatever is caught up in it.