Originally Posted by jsbihn

do you have the pass lock security light one?

In the mean time, one frequent cause is a broken wire that goes to the shifter (the break is located in the center console). These wires control both the key removal and the parking lock. If you have either of these problems then have the cable checked or you can fix it your self as indicated below:

shifter stuck or key stuck repair: Put the parking brake on, make sure the engine is off.
Put the shifter into 1 (farthest back position)
remove the shifter handle. To do this you need to loosen the allan screw (it is actually a torx screw but an allan wrench will work fine) there is a screw on the front of the shifter that needs to be loosened, pop the shifter console off the center console. There are 4 very hard to release metal clips that hold the shifter cover on. To release, you need to pull straight up on the shifter cover. Beware, you might break the plastic around the clips so be careful. The cover does come off perhaps with a lot of effort. If you are worried about breaking it go to a dealer for the repair.
once the cover is off you will see a cable and connector near a mushroom shaped button. This button is the one you pressed to release the shifter from park. Either the connector is off or the wires to the connector are broken due to the flex back and forth that occurs during movement of the shift lever. Find which wire is broken and fix it. It is preferable to use a small gauge, highly flexible wire to extend the harness to connector cable length. It is also preferable to use butt splices rather then solder joints.

problem: I start my truck and it stalls immediately or the truck just turns over but will not start
or i turn the key and truck wont turn over or i took the key out last night and the truck batteries are dead in the morning but i did not leave a light on, nor was there anything plugged in the lighter or accessory jacks

the problem is most likely a defective ignition switch. You will need to get a new one. The part number is gm# 15242754. It is a common gm part and most dealers will carry it as a stock item. Cost is about $40.

Remove the negative connection to the truck battery.
Remove the bottom cover of the steering wheel column cover as described in the stuck key problem procedure.
The key switch assembly can be seen on the bottom right side of the steering column.
You need to unplug the switch and then press in the spring loaded tabs that hold the switch in place to slide it out. There are several cables that may have to be moved around a bit but do not unplug the little wires that go to the top of the column if you do so, the truck will think this is a theft attempt and set the security alarm.

Once the switch is out, get the new switch and make sure the gear of the new switch is in the same position as the one that was removed. Put the new switch into the proper position and plug in the connector

hook up the battery

test that the switch works. If the gear is in the wrong position, the key either won’t come out or the key will not move to the start position (the spring loaded start position). In either of these cases you need to remove the switch and re-position the gear. Put the bottom cover back on the steering wheel column. Be sure to have the pieces aligned properly as it you don’t, you can screw up the locking tabs.