with a jumper wire with alligator clips on each end, ground the metal dash frame & see what happens. If nothing might need to drop the column a bit so you can take out the cluster (drape a rag on the col to protect it) & see if the round connector has fire to the pins but I imagine it does then see why (where) the printed circuit copper strips are not grounding to the dash frame and or why the dash frame is not grounding to the rest of the car body