Like playing with plumbing in an old building, touch one thing two things break, and then the fun begins
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I believe the "electrical thing" in the picture you posted in the fuel heater - your location says Georgia... You may or may not want that part - may if you see cold below 0°F, may not if you don't.
Cold diesel will gel in-place when it gets too cold - the parafin wax comes out of solution and like you would expect wax to do, turns into a candle where ever it is. If it's in your fuel filter you won't have fuel flow to your IP...