'99 Silverado 4.3

Has any one ever encountered hooking up a scanner to read codes, only to find the scanner acts as if it's not connected.
The scanner is fine. The problem is the feed to the DLC connector plug on the truck.
Any ideas on what the problem could be and how to fix it.

Thanks, Bruce

Version of Scan tool? Sometimes the info in the scan tool isn't set to read the version of your vehicle? IE: We have a Snap-on code tool at work but, it's only good on vehicles up to 98...

3/06 C.A.N. capable

Sounds like a power problem somewhere or a fuse is bad.I know one thing about the new Snap On scan tools,JUNK.All I here are problems with them and have to be sent out for repairs.The best one out there is Vetronix,Vetronix is ahead of everyone and it is even C.A.N capadable.Vetronix makes GM's scan tool Tech 2

Hell, i had my truck at the dealership one time a while back and they had the same issue with their scanner yet the day before it worked fine. He unplugged it and plugged it back in and wriggled the plug around a bit, then it worked fine. Maybe just a poor or dirty connection ?