The power seat won't work on my 1987 760, it is on the driver's side, is there any way to manually adjust the seat?
Not really but you can turn the seat over and try to turn the axles to make an adjustment. Do you have power to the seat? Is the fuse good? Can you hear the adjustment motor run?
It is probably the fuse. I had the same problem in my 87 Volvo 760. We popped in a new fuse and it worked with no problems