I have a 2008 GMC Sierra 1500. I tried to pull the engine bay fuse block to see the underside to determine which fuse the trailer power feed was connected too since I the fuse list on the underside of the cover did not show a listing nor did my Haynes manual.
In the process the truck appears to have gone into some sort of a theft lock mode (e.g. stereo display reads "XM TheftLockMode"). Interior lights will not come on, and truck will not crank. The gauge display will light up with the engine light and seatbelt lights the only indicators displaying. There is no security indicator displayed. Additionally, the key fob won't function. None of the buttons work.
If I disconnect the battery for a period of time and reconnect the radio will function for about 30 seconds and then go back into the XMTheftLockMode.
What is the solution to get the truck out of this situation?
Prior to this I've had no problems with the truck after 138K miles. 
In the process the truck appears to have gone into some sort of a theft lock mode (e.g. stereo display reads "XM TheftLockMode"). Interior lights will not come on, and truck will not crank. The gauge display will light up with the engine light and seatbelt lights the only indicators displaying. There is no security indicator displayed. Additionally, the key fob won't function. None of the buttons work.
If I disconnect the battery for a period of time and reconnect the radio will function for about 30 seconds and then go back into the XMTheftLockMode.
What is the solution to get the truck out of this situation?
Prior to this I've had no problems with the truck after 138K miles.
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