Tahoe power seat stops halfway back, now too close to steering wheel. We have checked the track for debris but nothing.

Do you have memory seats? Try holding the switch rearward for a couple of seconds after the seat stops or tapping it rearward a couple of times to see if you can overcome the memory stops the module may have learned. If it moves further rearward, hold that switch until you reach full travel in both directions. Let us know...