Check Eng Light , No codes

2001 jimmy,2dr 4.3 auto 4wd, Hey my check engine light is on, but when i take it to auto zone it won't power up there code reader?!#@%$?
What gives?

The computer is noe sending out information. Could just be a bad connection with the ALDL or it could be a bad computer.

Check fo 12 volt power and ground on ALDA test plug.
MT

Check fo 12 volt power and ground on ALDA test plug.
MT
Anywhere special on the plug? And can i hurt the comp by looking for a ground?

Did you check all of the fuses in both fuse panels with a test light?

Anywhere special on the plug? And can i hurt the comp by looking for a ground?

As Old Master said check all fuses and check for 12 volts on both sides.
Pin 4 is ground.
Pin 16 is battery power.
http://www.troublecodes.net/OBD2/

yep i did