Wait. Just hook a 12V test light from the DLC under the hood to a constant 12V source. If it proves out, then you know the dash bulb needs to be replaced. If it doesn't work either, there's no point in pulling the cluster.
I put the cluster back in and now it works. Weird. Now, I also found out what that STO-looking harness inside the cab is...my chime pigtail and the box was in the glovebox from the PO. Thought it was a brake controller or something.