My tilt trim gauge bounces sporadically while in motion and won’t move sitting still. I removed the gauge and sender and tested them both. They both work fine. While removed I connected them together using a spare battery for power. I rotated the sender dial and the gauge responded like it should. I also checked the continuity of the brown and white wire is it was good. He battery in the boat is good. I reconnected everything in the boat and no dice. It still doesn’t work. I am going to try and attach the ground wire to the sender direct to the battery to see if that fixes it. Any other ideas?