Posted this in the electrical section but wanted to get more exposure to some help diagnosing so here goes. I have taken the plastic Rally dash bezel out to repaint and redo the wood grain. It’s taking me at lot longer than expected because to many other distractions. Thus I hadn’t started and run the engine in awhile so I started the car up only to see the tach move up very slowly and then stopped. Prior to removing bezel the Tach had worked with no issues. While the engine was running the tach didn’t react to the throttle pumps. Then after shutting engine down the needle stayed where it where it had climb to about 1200 (see photo). I made sure there were no metal to metal contact between back of instrument cluster and frame work behind dash before starting the engine. The two connectors that go to the tach (blue and gray wires) are still attached. What would cause the tach to do what it’s doing? All other gauges worked fine. Any experience would be appreciated.
