I've had a series of back to back electrical issues following a battery replacement in my 1990 civic. Namely my blower motor and radio. I have the factory stereo deck, and the backlights come on, but it's not functional at all. All my fuses are good and I have voltage going to the radio, resistance looks fine on the blower motor circuit, but there is no voltage going to it no matter what position the switch is in which is WEIRD BRO. Also the blower resistor isn't corroded but its all jacked up like someone stepped on it or something. I also tested the motor with wires straight to my battery and it works.

I figure I'm gonna buy a resistor, see if it works, and buy a new dash switch if it doesn't. And if THAT doesn't work I'm just gonna cry and poop my diaper.

Why would these things happen suddenly after replacing a bad battery?

Thanks