shlbsnake

Hello, I am working on a freinds 99 silverado with a 5.3 in it. He said the service 4wd light would come on and so I told him I would look at it for him. The light was not on and the 4wd worked perfectly. I drove it home and the message came on so I stopped and put it in 4hi and there it stuck. I then got it stuck in 4 lo and it would not come out. Everytime I cycle the igniton the motor actuates but it is still in lo. I finally got it into 2wd but as soon as I cycled the key it went back into 4lo. After awhile it is now back in 2wd and I unplugged the motor.When the key is turned on the 4low light flashes then all the lights go out and I can't do anything. I can't find a connector pinout but my readings are as follows with truck running- 6 pin connector: 4 pins have 5v, 1 has 8v and one ground. The 4 pin connector 1 has 12v 2 have 5v and the other has 0 and is not a ground? I have read about the encoder, the motor and the switch all being common problems. Any Ideas?? sorry for the long read and thanks,
Tony