2001 Dodge Caravan

Not sure why rain would affect it but a common source of that trouble is the ignition switch contacts and burned / overheated connector terminals. This happens much more often to people who use the heater fan on the highest speed quite often. Two ways to verify it's the switch are to wiggle the ignition key when the problem occurs, and to use a voltmeter to monitor the voltage leaving the switch on that circuit. If wiggling the key makes it come back, that's fairly conclusive, but if it doesn't make things start working, that doesn't mean anything. It still could be the switch.

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