I recently replaced my battery on my 05 Mini. I decide to go for an aftermarket battery. After installing the new battery on my car. I experienced a few problems. My a/c does not work, A/C buttons don't light up at all. Also my headlights are always on. I am not able to turn them of at all. Has anyone experienced this problems before??? Can anybody help me??

 

You might have spiked the ECU I'd try removing the ground and letting it sit for 1/2 hour and try reconnecting