I have a '96 Chevy Astro Van that the blower motor fan turns on by itself when the van is off. It had never done it before until a few weeks ago. I've been told it could be a relay. Any suggestions?
What's the weather like? If it's warm out where you are, there may not be
anything wrong with it. Electric fans are controlled by a thermostat, so
when the coolant temp gets to high, the fan turns on. It's not too uncommon
for a car sitting in a parking lot to do this even after sitting for
several hours (at the supermarket in the summer when it gets up to 30-35C
up here, the fans on random cars will turn on and off).
Past that, yeah, it could be the relay or the thermostat could be sticky.