My automatic seat will move to every position except forward and backward. What could be the problem?

These devices use motors with worm gears to provide the smooth operation and torque necessary to move the seat. The most common problem, other than the motors themselves failing (and since your does move somewhat, the motor is probably OK), the next biggest issue is something gets caught in the gear drive. Get a good look under the seat and see if there isn't something jamming the forward-backward motion of the seat.

is it electric or manual... electrick the cog is worn. manual the spring has be come weak either way you will need to take the seat out to fix it.

Check that the seat belt mount (often solid plastic or metal that holds the button side of the belt in place next to the center console) is not pinching and preventing the seat from moving forward and back. This happens on many Fords, so it might happen on some GM's too.
If you can hold the buckle mount out of the way while someone else moves the seat backward (or forward), it usually starts working OK again until someone moves the seat to the max forward or max backward position and it gets stuck again

To manually maneuver a power seat because the automatic feature malfunctions, carry out the following steps:
1. Turn of the engine, remove the batteries for safety reasons
2. Ensure that you have the following tools at hand-winder, screwdriver, pliers, knife, gloves, bolt cutters, and safety glasses.
3. Remove the entire rear seat
4. Cut the spring mesh below the seat with the bolt cutters-this will expose the shafts
5. Turn the shaft left to move the seat forward, and turn it right if you want to move it backward - keep turning until you get the desired position
6. Now test if the seat is in the correct position and put everything back in place
One of the many motors in your seat is not working properly, so it may need to be replaced. The problem may also be caused by faulty wiring or a blown-up fuse.

Only if u take the seat out to get at the rising ratchet.Hope this helps.

On ABS light most common problem is ABS control module , they failing left and right.
As for the seat adjustment , sound like you need a new seat switch.

the wirering for the drivers seat will have a wireing harness under the carpet this is the best way to tap into power for the seat

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.

The reason is that your sliding grips have been slipped and therefore jammed at one position.

Remove the seat open it's sliding grips and replace it.

Good day;
What year is you car? Does the other controls work for the seat? and just to clarify the seat won't go forward of back?


Cheers