If I remove the remote battery disconnect from the system, everything works as normal, so nothing is broken.
With the battery disconnect installed, the glow plug relay does not go 'clunk' but all other power works and I can crank the engine.
EDIC fried a long time ago, so there's no electric start.
To activate the glow plugs I turn the key to 'on' so there's power to the system and then I hold down one of those manual switches, (I upgraded the original B engine to a 3B). When it works I can clearly hear the relay clicking on.
The battery disconnect says it's rated for 230amps, is it possible that the glow plugs exceed that?