Wierd 2001 Silverado cluster issue

I have an 01 Silverado 2500 HD 6.0L. Cluster was acting wacky, seemed like it was shorting out intermitently then it finally stopped working. I brought it to a local cluster repair facility and they told me it checked out fine. After putting it back in my truck I found that plugging in the cable from my scan tool to the computer port gets it to work perfectly fine, but when I try to read my truck for codes through the same port I get a "cant communicate" reading. Anyone have a clue whats going on?

I have an 01 Silverado 2500 HD 6.0L. Cluster was acting wacky, seemed like it was shorting out intermitently then it finally stopped working. I brought it to a local cluster repair facility and they told me it checked out fine. After putting it back in my truck I found that plugging in the cable from my scan tool to the computer port gets it to work perfectly fine, but when I try to read my truck for codes through the same port I get a "cant communicate" reading. Anyone have a clue whats going on?

check ALL FUSES . use a meter ..it may be the cigarette/power ports circuit blown..

could also be LOOSE fuse sockets..if thats all good check all grounds in the engine area..then at the other locations.

my 2002 1500 did same thing even working with scanner . my quess is that is grounding you pcm because i clean pcm it was full of water and all corroded . cleaned it and every thing is fine . I have a blog on here : security lights stay on and more . dealer did sell me an ignition switch that maybe i didn't need but they did me right by hours od diagnoses