1998 Lexus GS 300 blower

Air Conditioning problem
1998 Lexus GS 300 6 cyl Two Wheel Drive Automatic

This is really a two part question.
1st. If the a/c is still blowing cool air it's just not going to full speed does that mean the motor is going out or just the top 1 or 2 speeds no longer works? If so is it rather easy to just replace the motor?
2nd. This deals with the auto door locks and remote door lock/unlock. A few of the doors won't automaticlly lock. I changed out the battery on the remote but they don't even work from the inside door switch. I have to manually flip them. Is it a cylinoide that has gone bad and needs to be replaced?
Thanks,
Tim P