I've been trying to remedy a problem with the issues listed in these two threads. http://www.tahoeyukonforum.com/threads/electrical-issue-is-expanding.93566/ and here: http://www.tahoeyukonforum.com/threads/intense-electrical-issue.92892/page-2#post-1113447 Short story now is that there is a no start or crank condition. Despite replacing the ignition switch (or operating it manually when removed from the lock cylinder for that matter) turning it to the start position does absolutely nothing. The gauges don't even drop to zero as is usually the case. Removing the key will not turn off the gauges or indicating lights either. That is accomplished by disconnecting the battery. What's more, what appears to be normal dash function (after disconnecting and reconnecting the battery), will allow the radio to be turned on. However, that will only last for a minute (or less) before it shuts down and displays "LOCKED". In all of my fiddling is it possible that I've activated the theft deterrent system? If so, what is the remedy? HP Tuners or similar software to access the PCM?