OK, first grab a multimeter and check you've got power both IN and OUT of the fuse panel. Then, I reckon you should see if your instrument cluster is properly grounded, loosen the screws then tighten again. Recommend adding an additional ground wire because there are a lot of opportunities for poor grounding (paint, plastics, rusty screws, the inside of dash shell is rusty, dirt, list goes on (I painted inside mine, which was where the problem began! LOL)