Another problem! Bad ECU?

[Dave145]

This morning when I went to start my truck, it started fine but had no gauges or lights on the dash except the check engine light. Let it warm up for 15 minutes, then it was fine. Figured it was just cold or something and went about my day. Then when it was time for my lunch break, I hopped in and fired it up to find...the exact same issue. So I drove it to the local parts store with no dash and a check engine light on. Once I turned into their lot, bam it worked. For ***** and giggles I yanked the cluster fuse out to check it, causing it to go dead for a minute. Plug the fuse back in, and back to no dashboard and a light. Had the store read the codes it was throwing, and the one that came up indicated that "no test data was stored" in the ECU. Guy at the parts store told me that meant the ECU reset itself again and that it's going bad.

Does this sound like a bad ECU? Or a bad battery? Battery gauge shows in the middle, so I assume the battery is good...

Reason I ask is because the dealership seems pretty unwilling to fix it, even though I just bought it last night. So now I get to probably fix it myself. Woo!