9 Pin Data Link issue

[Grizzly]

2010 Peterbilt 387
ISX
Data link is stopped communicating with mcp50 by Omnitrac. Thought it took a crap from being old, but installed a new IVG and it’s not getting power either.
What I’ve checked and know so far:
All fuses behind glove box checked with ohm meter and test light. All good.
Checking pins on data link plug:
Pin B (power +) light the tester
Pin C (CAN J1939 HI (+) When I touch it, no light, but kicks my high idle off.
Pin D (CAN 1939 LO (-) gets nothing. And I can’t remember for sure if it was this pin or not but ohm meter didn’t zero out.
Keep in mind I have minimal to zero electric know how talk to me like I’m 3 lol.
Thanks