I bought my truck used and do not have a keyless unlock remote. Usually if you lock the door and close it, the unlock buttons inside on the doors are disabled so you can't just reach in through the window and unlock it. When I unlock the door with the key the unlock button on the door is supposed to reactivate so I can unlock the passenger side. For some reason it is not reading my key unlocking the door. This means that when I use the key to get into my truck the unlock button on the door panel doesnt work, and when I put the key in the ignition the alarm goes off until I start the car. Once the car is started the unlock button works again. Anyone have any ideas how to troubleshoot this? I have no idea where to start.

 

It sounds like the key switch is not connected to the driver lock switch module. I don't understand why the alarm doesn't go off as soon as the driver door is open, though. Do the courtesy and dome lamps work? Maybe the driver door ajar switch is disconnected as well. You'll need to take the driver door panel off to troubleshoot. Check out How To Remove Truck Door Panels - 2002 Chevy Silverado Extended-Cab Pickup.

 

I will take a look as soon as I get a chance. Funny thing, I went to show a coworker today, and the lock did not malfunction (the unlock button DID work after unlocking the door with the key) but the horn still sounded when I put the ke in the ignition like I was stealing it again. Of course it stopped after I started the truck. Strange stuff...