Well they've had my truck since yesterday morning. They said the solenoids looked good and they couldn't see anything wrong, but they did experience the problem yesterday.

They said they called Chevy tech support for ideas to look for and they thought it was electrical and to trace wires.

Today they said its the Power Control Unit/Module (I don't remember if they said unit or module lol).

Does that sound right? Could that also have been causing the speedometer/tach sticking issue, or do you think that's still a separate issue?

I just want to make sure they fix it right and that I'm not getting screwed over lol.