Do you have 12v desktop power supply to test the board with before you place it in the vehicle?
2 things you want to comfirm.
1 ... what input does the compass need to respond to those signals. 12v or ground.
2 ... what is signal in the car, at the cluster, that you'll be tapping into for the compass?
If memory serves me correctly. Your dash signals are 12v when active. What is the compass calling for.
How are you connecting the power distribution your dash electronics?
I ask cause I have built a module that acts as a power distribution center that is fused at 10 amps. It ties into the kitt voice box and activates the dash AFTER the count up sequence is complete. Like in the show. ... info can be found in the merchandise section of this forum. I current have 2 ready for immediate shipping.