I found the best way to trouble shoot the dash bezel is with the schematic in front of me along with a 9 volt battery, a bunch of alligator clips and a 90 ohm Potentiometer.

I had painted my gauge cluster and nothing would ground correctly. Had to do a bunch of scraping and then it worked like a charm.

Please note: Do not to put voltage across the current gauge. It will peg hard and smoke will come out:)