I'm not sure why you are burning up the Moss voltage stabilizers. Maybe the Moss voltage stabilizer isn't up to supplying the necessary amount of current in some scenarios. More current is required as the temp sender encounters higher coolant temps and the fuel tank sender is reading a full tank.
I don't see any capacitors in their design to help smooth things out, but not sure if that is really required. E.g. what if the fuel tank sender is a bit erratic and sometimes cycles between normal resistance and infinite resistance? I have a solid state voltage stabilizer from fellow Sunbeam owner Joe Parlanti (
http://velocesolutionsllc.com/Voltage-Stabilzer-Stabilzer-1.htm) that I have used for a few years on my Series V. It appears to have a couple of capacitors under the shrink wrap.
Here are photos from the Moss site:
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Picture above is of a positive ground item. But I assume the negative ground item also has "B" and "I" connectors and the housing is the ground connection.
I assume you have negative earth on your Alpine.
The voltage stabilizer is being grounded by its housing's mounting screw. Any chance the ground connection could be flaky?
The "B" connection is connected to a wire that is hot when the ignition switch is in the 'run' position.
The "I" connection goes to each of the fuel and temp gauges.
Here is the original series V circuit, which you are reproducing with your new wiring harness (possibly with a different fuse scheme...)
View attachment 25196
You can double check the gauges by removing the wires and measuring the resistance across the connectors on the gauges. You should see 61 ohms.
Mike