I'm working on a '99 2500 Suburban. My issue is when I push the power lock button, in the lock or unlock direction. I only get 3 of the 5 doors that will lock and unlock. I can see the passengers door lock moving about half way with either function. If I push the button 3-5 times to lock or unlock, the system acts like it is loosing power and will no longer lock any of the doors. I can still hear the locking relay clicking, just no power getting out to the actuators. If I wait about 5 minutes, it will work fine for 3-5 pushes again, then just relay clicking. I get the same results using the key fob. I have exchanged the lock relay, and the drivers side power lock button from my parts vehicle and have the same results. Where do I look next?