Power seat will not function on the very back of the seat to raise and lower it.

Check under the seat for wiring issues (disconnected). Check to see if there is power to the motor when you select that function. If there is, the motor is the problem. If there is no power, check the switch to see if there is power out.

I am assuming you are talking about the third row power folding seat. Has it ever operated? If it is new for you, there is a specific procedure to get it to function. I believe it involves pressing the keyless transmitter unlock button three times. If you have never had it operate, and/or it is new to you, refer to the owners manual for description. If you have no manual, or other questions, reply to post.