Intermittent radio and gauge failure (ground or loose connection)?

So, yesterday I had a 4x4 light come on at start up. I turned it off, it went away. About 45 minutes later I had an intermittent failure of the radio, tachometer, and speedometer. All failed then after restart they fired up again. Today I cleaned the terminals on the battery (the positive connection was slightly loose) checked grounds in engine compartment, had both the battery and alternator checked twice. All good. Ran codes all clear except a suggestion to replace an ABS control module. But it’s not throwing any codes. Ran it about 35 miles today no problems. Suggestions? Could it just be an issue with the positive battery connection being loose?