04 Denali cluster troubleshooting question

[clay68c10]

Hey GM techs!
Not the typical stepper motor failure.
A relative has an 04 Denali and the cluster has an intermittent total failure. No LCD readout, no gauges move. Will work for a day, then not. Was out for a few weeks recently. It was inop when I started looking at it today.
Pulled the cluster, opened the back, took a peek at the back of the circuit board and didn't see any obvious solder cracks at the connector pins.
Found this wiring diagram online; http://www.justanswer.com/chevy/36yc...e-cluster.html

I'm guessing the power/ground is the same in this diagram as it would be for the Denali.

I have constant 12v @ B11, switched 12v @ B9 and ground @ B12

The serial data lines show a flicker of A/C voltage (<1v) when the key is switched on (I consider that normal)

Cluster did start working again after I called it a day and plugged it back in. Stayed working thru a few key cycles and the car left.

I'm thinking that something on the power supply in the actual cluster is taking a dive, but I want to make sure I'm not missing something on the vehicle side.