Glad it worked out, guessing that loose glow plug wire may have been shorting out.
If it happens again -
Make sure fuses U (Fuel heater) and K (FSS, Glow Plug Controller, cold idle advance, IP advance.) in the engine compartment and #17 (Glow plug controller.) in the interior fuse panel all work. I would pull them, look at them, test for continuity, and plug back in or replace if bad.
Something to also look at is your FSS shares power with the idle advance and IP advance when your engine is below 112 degrees. Your FSS also shares power with one of the terminals on the glow plug controller. Perhaps when you did your timing you bumped one of those cold advance solenoids and it broke, shorted out, or the wiring harness gave out. Thus when the engine is cold you have no power to the FSS (Shorting out of grounding out.) but when hot (Over 112 degrees) the switch breaks the circuit to the advance items and the FSS no longer shorts out.
Now the wild card, how is your breaker hooked up? That is a custom fix, so help us understand where and what the breaker is hooked to. It could be this change to your wiring could be related to your issues.