GMC Repair: power locks, yukon denali, power door locks

Question
The front driver and passenger power door locks on my 2000 Yukon Denali 5.7L only move about half way when locking or unlocking with the switch or key fob. Both rear door locks work fine. How can I trouble shoot this?

Answer
Hi
It is MOST likely the Actuators  for the misoperating doors.
This is how these particular  actuators act when faulty.
I Looked in schematic and see no way to pinpoint the 2 fronts as inop seperate from the rear. It will be either one inop or all inop.
I would check the actuators.
Hope this helps.
Pawl