I have a 2005 Silverado Z71 with 5.3L engine. Runs great when it runs. Sometimes (maybe once a month) it will not start. Turn the key....nothing. No sound, gauges work, radio and lights work...just will not crank. The battery and charging system are fine. I have jiggled the gear selecter, put my foot on the brake...doesn't help. Usually if I lock/unlock the doors either by remote and/or by door switches, it fixes the problem. It can take several repeated attempts to get this to work. The computer is not throwing any error codes. Sometimes, if I just wait 10 minutes or so, it fixes itself. It is annoying, especially if I have an appointment. Mechanic won't work on intermittent issues. This has nothing to do with temperature or whether the engine is warm or cold. The problem seems to be in the security system (lock/unlock resets system??). I have read this same report from many other Silverado owners so it is not a unique problem. I have not found any answers other than to start replacing various parts until something works. It would seem that with so many reports of the exact same issue, there would be some part that is most likely the problem. The dealership is not helpful....they just want to rack up shop time. Any ideas?