I ran into the same issue when I didn't have a good dash ground. Neat things would happen when I hit bumps, sometimes indicator lights would come on, sometimes the dash lights would go out, etc.
I
THINK there is a clip on the factory wiring harness that clips onto the gauge panel, or maybe it goes somewhere else...can't recall
I would run a simple wire from a known good ground to a screw on the back of the gauge cluster.