The electric seat adjustment on the driver's side of my 2000 V70 works in three of four directions. Does the whole gizmo have to be replaced or is it an smaller fix?

 

Well, it could be a number of things, you really have to be specific. Does it not go up or down, does it not recline, what is it not doing? Could be a switch, motor or cable problem. Post back with specifics.

 

It does everything except move forward. It tilts, moves up and down and backwards. Just not forwards.

 

When you move the switch can you hear a sound? Does it move back? If you hear the motor but have no movement, you probably have one of two problems. 1. There is something stuck in the seat strack like a coin stopping it from moving. 2. The cable could be bad and needs adjusted or replaced.

On my 960, it is common for the cable to be out of adjustment and only one side of the seat moves when it is adjusted forward or backwards. I usually tape the cable in a certain possition to get it to work again. I'm going to try to use the cable repair method for the 850 recliner repair this weekend and heat the cable end and press it in a little to see if that is more of a permanant fix.

 

The preset buttons can move the seat forward but the up and back button cannot. Unfortunately, the preset buttons aren't set for my new 16-year-old, 5' 3" daughter.

 

Sounds like a button problem. They come apart on my 960, not sure about the S70, it's at school with my daughter. What I did with the 960 was take the seat panel off, the one that has the buttons, then remove the torque screws to get at the buttons in there. BE VERY CAREFUL TAKING THAT SWITCH ASSY OFF THE SIDE OF THE SEAT, THE AIRBAG TRIGGER IS IN THERE. You may see a red clip that you can put in the switch for safety reasons. I'll send you a link to view the one on the 850 models.

It's the 4th pic down: https://volvoforums.com/forum/volvo-850-16/850-seat-back-cable-repair-16364/

 

Mine did exactly the same thing, went to a junk yard and got a new switch.
Problem solved.