Happily, I had earlier found and installed a combination ammeter/voltmeter/state of charge display device to replace the JLD404. It also functionally replaced the ammeter and fuel gauge that were driven by the AutoBlockAmp, so when that failed I was in no hurry to deal with it. We've had a solid week of rain and I took that opportunity to remove the failed gauges and tidy up the basket of snakes behind the dash.
In the rush to completion in 2012, I had just loaded in the dashboard components and put a zip tie here and there to keep the stray wires out of sight. Not a pretty sight and not very maintainable, so this seemed like a good time to make order out of chaos.
Removing excess wire length and encasing everything in split loom makes a huge difference. No one will see it, but it will give me some peace of mind knowing that things are secure and not flopping around back there. I replaced the fuel gauge with a clock from Speedhut with the same face design as the other gauges, then promoted the combo volt/amp/SOC display from its separate bracket below the dash to cover the hole where I removed the old ammeter. It stands a bit above the dash surface, but puts that info in the line of sight. It's a departure from the vintage analog look I started with, but more useful.