I live in the rust belt in Canada.
Rusty connections are 'very' temperature dependent and one always finds out the battery connections need cleaning after the first cold snap, never before.
Have you check the computer's plug for a green pin or green socket? A green stain means a corroded connection.
The oxidized fuse leg is also very common up here. My wife and I were just comparing notes on that and I think we have had 4 vehicles in the last 20 years that had that 'no start and no lights' issue including our Cherokee. On one Volvo 240 is was the fuel pump fuse, the others were low power ones like for the ignition module.
Mike