Looks like a grounding issue to me. With a similar problem in the gauges and CC unit, I found corrosion in a couple places; the grounding strap between the frame and the bell housing, and corrosion in the instrument cluster. The latter relies on metal contact between the three units of the cluster that tends to get corrosion over time. In my case, cleaning those contact points with a pencil eraser and cleaning the contact points of that grounding strap under the car, took care of the problems. I'd also look at the grounding points for the entire car which are on the firewall behind the left AC vent.

These are all the ground wires on the firewall;